Flats or houses?

So almost all flats are appreciating given they're near or are in a demand zone. But then, if you buy a flat, it's 20-yr loan period and if you sell after 20-yrs then won't that be difficult to sell because buildings do get old, and unless there's some builder who actually takes up the reconstruction/maintenance, I have no guarantee what's going to happen to the building or if I sell within first 5-yrs when it's selling like hot cake, then the purpose of staying in one place doesn't fulfill because I will have to find and move.

So isn't it better to go for houses? I agree it's on the expensive side + security and other stuff. But do you actually think these flats which sell for 3-4-5cr for a 2000-3000 sqft will become 10-12-15 cr in 7-10-12 yrs?

Anyone who has seen this whole cycle where flats were super expensive then there's a bearish markets for flats and then it started selling again?