Construction company wanted in the Stuttgart metropolitan area!

Well, I can understand the companies, what you’re doing are indirectly "lowest price" calls, nothing more. I think the providers get more than enough of such inquiries, and then I can understand that they primarily take care of those who show commitment, invest time, and genuinely mean business. After all, at least 19 companies end up by the wayside in your case.

My inquiries are not "lowest price" calls, but I want a brief and concise house concept (i.e., where the focus lies, e.g. heating/ventilation from a single source, basement or other trades from the same company, cool multi-layered wall, passive house, a special ETICS, architecture of the house...). Unfortunately, this is often not evident from the catalogs. Likewise, I want a list of typical elements that belong to the turnkey house (architect, specialist planners, possibly insurances, construction management) and those that do not (e.g., earthworks, expert reports, etc.). The construction service descriptions are often very confusing and unfortunately not sorted according to DIN standard 276 costing groups. I really feel sorry for the poor remaining 19 construction companies; they earn so little in these difficult times...

First you want prices for standard floor plans, but then concrete offers for a custom house?

You misunderstood me. I meant that companies have enough floor plan models/drawings in their drawer that they can finish and hand over to a customer in 15 minutes. In most cases, changing the floor plans, i.e., moving a few walls, does not cost extra. Most are flexible here.

What good is a 20-minute price if it’s poorly prepared and incomplete? There are so many factors that influence the price in house construction that you don’t even notice at first glance. For some, these are included in the standard, for others not. One hour is not enough.

I am not concerned about the exact price, which can later change significantly due to various extra requests anyway. What matters to me is the construction service description and priced options and whether the companies are flexible with the floor plans, i.e., can roughly work with my desired floor plans. I absolutely agree with you, a price comparison between providers is almost impossible. Precisely because when the construction service description only says "insulation X cm" or "central ventilation," you never know what you will get. And in the purchase contract/construction service description, there are asterisks everywhere and then at the bottom "or comparable" or "according to statics," etc. The consumer advice center’s books contain dreadful things about what construction companies can/want to do with you according to the contract. (see attachment, from: Purchase and construction of a prefabricated or solid house, p. 215). I recommend everyone read this beforehand.

It is simply not a buyer's market at the moment.

Why should the construction companies bother to provide what you would like?
Initially, it just costs money and time.
In the current environment, I don't see any advantage for a construction company.
Some companies are booked up for 2 years. So why should they invest additional money to maybe have slightly better chances with customers who want to compare 20 companies as quickly and standardized as possible?
And that with a product (house) that is hardly comparable by nature.

That also explains the strategy of arranging as many personal appointments as possible. I could almost bet that the closing chance for the salesperson is many times higher. And from the house building company's perspective, presumably also the target group they want to reach.

Whether you actually gain anything from such a comparison is questionable. What use is a standard floor plan that I don't like and maybe doesn't even fit a possible house on my lot?
Maybe companies are excluded that could have offered me the most suitable overall package, but whose philosophy is to make offers, floor plans, etc. only after personal appointments.

I can certainly understand the desire, but I’m not sure if this approach necessarily leads to the most suitable provider.

And that with a product (house) that is hardly comparable due to the nature of the thing itself.

I think house offers are quite comparable if you include correspondingly precise construction-related specifications that apply to the plot and the new build. For example, I have sent almost all providers the same documents with specifications such as roof shape, ridge height, roof pitch from... to..., usable building area, KfW standard, number of floors/knee wall height..., sample floor plans from basement to upper floor that make sense for the location of the house, e.g. living areas facing south/west, space-saving staircase, etc.
In addition, there are standard things that almost every house has, for example, on the upper floor: children’s room, bedroom, dressing room, bathroom. There is not much to change here unless you have 100-150 sqm left on the upper floor :)

Possibly companies might be excluded that could have offered me the most suitable overall package, but whose philosophy is to only create offers, floor plans, etc. after personal appointments.
I can certainly understand the wish, but I am not sure whether this approach necessarily leads to the most suitable provider.

I agree with you, but which way would be more sensible then? 19 disappointed companies, each with whom you have held 2 personal meetings and had consultants travel many kilometers?

I think that house offers are definitely comparable...

If an architect makes a tender with an exact specification of services, then maybe. Just look at the descriptions of construction services from the different providers. You have solid construction and prefabricated (by that I mean timber frame) houses in comparison. You really don't even know where to start with all the differences.

I believe you have a different understanding of comparability or have not been reading here long enough.

I agree with you, but which way would be more sensible then? 19 disappointed companies, with whom you have each had 2 personal meetings and consultants have had to travel many kilometers?

No, based on the information you consider too little and some asking around and recommendations (e.g. in new housing developments), you pick a few favorites with whom you then deal more closely, or also take the personal conversation.

If things go in the wrong direction, you can always talk to more.

For example, I sent almost all providers the same documents with specifications such as roof form, ridge height, roof pitch from...to..., usable building area, KfW standard, number of floors/knee wall..., sample floor plans from basement to upper floor that make sense for the location of the house, e.g. living space facing south/west, space-saving staircase, etc.

And exactly with that you have
1. shown the providers that you still need to be guided sales-wise, as well as
2. triggered them to want to recognize in the further process whether you are an interested party or a last-price inquirer.

Also a note from me. You criticize that the glossy brochures have no significance, but when a provider invites you, the distance is too far for you to travel. I found this "pre-sampling" at Schwörerhaus very informative. There, things were selected right away and included in the offer, so that no large additional costs surprised us during the actual sampling.