Well, renovation of buildings tend to cost more than razing the place and building to your needs. My work is an example. The building my state government office is in was built to be a small junior college that out grew it and moved out. The building was rebuilt leaving the main parts of the two floors but neglecting the basement and the only reason was the political flack if the building had been razed scared the people who controlled the money, and it was rebuilt, but cost 1.5 times the cost of razing and building to need would have.