Construction costs are currently skyrocketing

In my impression, "in the past" people with less well-paid jobs also built and were often sole earners.

In the past, there also seemed to be more "less well-paid jobs." Now there are more engineers, more computer scientists, fewer manual workers. Applied leisure sciences are studied where previously an office clerk would have sufficed (and perhaps even better). The high school graduation rate has also increased. I would rather call that inflation; you also have to shift the line for when a job is considered well paid. Just because someone works in an office today doesn't mean they are well paid anymore.

Or put differently, in the past poorly paid jobs were not that poorly paid after all ;)

In the past, there also seemed to be more "less well-paid jobs." Now there are more engineers, more computer scientists, fewer laborers. Applied leisure sciences are being studied, where previously office clerks would have sufficed (and maybe even better). The high school graduation rate has also increased. But I would rather call that inflation, as you also have to shift the line for when a job is considered well-paid. Just because someone works in an office today doesn't mean they are well-paid anymore.

Or conversely, poorly paid jobs weren't actually that poorly paid back then either ;)

Today you have to offer added value that a machine cannot provide to get good pay. There are still many office clerks, but the profession is losing importance because many of these tasks can now be automated. This is also happening in many other sectors. You can either complain about it or adapt. The fact is: jobs that require little education are increasingly being automated away or taken over by robotics. If Homo Erectus had vehemently resisted any evolution, we probably still wouldn't have a wheel or climate change today, which has its own advantages.

It is still a mystery to me why someone with a very high monthly net income of 4000 euros should no longer be able to build today.

And why so little equity is available for many. Sacrifice is simply not so popular. You always have to make compromises.

So nobody needs to complain. The do-it-yourselfers are not found here, they are working hard on their construction site and not sitting around at the computer.

I can certainly remember that hardly anyone could afford to build turnkey. That is a rather modern phenomenon. Practical, safe.

But in my time maybe 20 percent got their Abitur. Today it is well over 60 percent. There can only be 2 possibilities. Either the Abitur has become significantly easier or the students are much smarter.

Does the builder want to do any helper work on his construction? No. Does the builder want to stand on the construction site 18 hours on Saturday and Sunday? No. Well then he just has to pay.

So I drove 300 km to my construction site on Friday noon, after a short coffee put on work clothes and worked until 10 pm. Worked Saturday and Sunday from 8 am to 10 pm, Sunday evening drove 300 km back home.

Got up at 5 am on Monday morning and went to work.

Week after week, for 2 years. But also built without credit. And so I have been living without a mortgage for several years.

And during the week I then organized materials.

So don’t complain, just get it done!

Well, a few times the account was overdrawn, the money was gone, but somewhere I quickly organized something again. The world doesn’t end because of that. If necessary, you could always have taken out a small loan.

...and without any judgment, but to get out of the tunnel vision a bit: Property = new single-family house? What about buying used/existing? What about ETW?

Well, we looked at everything. In the end, the existing houses were simply way too expensive considering the renovation needs. You can't ask for almost new-build prices but have >100k renovation needs. Additionally, with existing properties, you always have the problem that you lose a lot of money to incidental costs. Realtor, property transfer tax, notary, and you've sunk 50k without any lasting value. New development area from the municipality -> no realtor and with our 68k land price, tax and notary fees are not that significant.

Well, we looked at everything. In the end, the existing houses were simply way too expensive given the renovation needs. You can't ask for nearly-new-build prices but have >100k renovation costs. Plus, with existing properties, you always have the problem of losing a lot of money on additional costs. Realtor, property transfer tax, notary, and you've sunk 50k without a lasting value in return. New development area from the municipality -> no realtor and with our 68k plot price, tax and notary don't weigh as heavily

It was similar for us. We actually really wanted to buy an existing house and after almost two years found nothing or rather ended up getting the building plot. The construction project is now a bit more expensive, but I don't have a terraced house from the 60s where nothing has been done so far. Of course, this might not apply to all regions, but especially in 2019/20 I had the feeling in our region that existing and new builds were almost on the same level - of course only if you found a plot that was reasonably priced.

Either the Abitur has become significantly easier or the students are considerably smarter.

Or your assumption is based on the faulty premise that in the past every student who did not obtain the Abitur was not smart enough for it.