>>1734500>It's not the foundations that worry me, but rather the force being applied high up on the upper floors.Thanks for the clarification, I agree with your concerns.
Apparently the towers have a concrete core and a lighter concrete outer structure.
Many more concepts were proposed, some of much more ambitious than that one (
https://www.ihmezentrum.info/wp-content/uploads/2019/05/2018-Doku-Brutal-Sch%C3%B6n-21x21cm-komplett-Stand-03.08.18_Webversion.pdf), but the issue is financial in nature. The current owner of the structure has not found the right business model to make profit. The city is the biggest renter, renting the majority of the available office space. There is also the issue of the apartments that were sold to individuals throughout the years, those make any big reconstruction project a huge issue.
>Whether filling it up or not will work will likely depend heavily on getting people to live there who have some purchasing power and to add the appropriate shops.What caused the project to fail is that it had to compete with retail in the city center (2km away). Other than that, corporate direction changes, mergers, bankruptcies... in the companies that used to rent retail space in there caused them to either shut their doors for ever or move to smaller spaces in the city center.
This part of the city could really do with a big furniture store (one of the biggest stores in the building before it failed was a furniture store chain that later went bankrupt). IKEA is testing new store concepts inside cities instead of huge warehouses in industry zones but I do not think they would want their logo on a dilapidated structure.
If I had absolute power and infinite funds I would repurpose the whole structure as a a university campus. The local university has 180 buildings scattered across the city and outside. With around 120.00m2 of floor space, this one building could accommodate a large majority of the university's activities.
