Well... That assumes willingness to build new things rather than miserably put up with the decaying things left to us by previous generations. They're re/build

Well... That assumes willingness to build new things rather than miserably put up with the decaying things left to us by previous generations. They're re/building about 50 a year, and there are 32000 schools, so about 0.15% of the stock per year. So a school has to last over 600 years on average before it'll get rebuilt at this rate.