That's how it is. I lived as a student in the Olympiadorf in Munich (a part of it was designed as a student dormitory). The buildings have slowly deteriorated because the concrete had flaws. But any changes had to be approved by the architect.
Now, years ago, the original bungalows were replaced with new ones (because a renovation no longer made sense and the bungalows, which were still comfortable for us, were downsized, so that more could be built on the same area) - this also only happened with the architect's approval.
However, I believe this does not apply "for a lifetime" but exactly 70 years - as is the case, for example, with compositions.