Multi-division house introduction yes or no

how many houses, like those built in the thousands, do you know where the KG pipe still does not serve its purpose today?

Alone I know - due to my profession - a high three-digit number of houses that were built within the last 4 years where a KG pipe does not serve its purpose. The reasons have already been mentioned here. Radon, landfill gas, water...

Alone, I know - due to my profession - a high three-digit number of houses that were built within the last 4 years where a KG pipe does not fulfill its purpose. The reasons have already been mentioned here. Radon, landfill gas, water...

Can you explain that? For example, with radon, I know it can be in the drinking water, but the MSP does not change that. Is it then about preventing radon from the ground from reaching the pipes? If yes: How can this be solved differently with an MSP than with a sealed KG pipe?

So for example with radon, I know that it can be present in drinking water

It can. However, it does not remain in the water for long, as it quickly transitions into the atmosphere. That is also the crucial point: radon is a gas, so it enters residential buildings through improperly and unprofessionally made building penetrations. Especially in southern Germany and the low mountain ranges, radon (or more precisely its decay products) can become a problem in poorly ventilated basements.
Corresponding multi-utility solutions are - demonstrably - gas- and watertight, also against external pressure. Any DIY construction site solutions with somehow concreted-in sewage pipes, subsequent building and well foam extravaganzas, or the insertion of annular gap seals into the KG pipe (for which the annular gap seals from Kr*** and Doy** are, to my knowledge, not specified) are by definition not state of the art, nor recognized engineering practice.