What do they do with the old ones if they don't sell them? Also, as far as I can tell Apple does a decent job of maintaining a stable price even with inflation

What do they do with the old ones if they don't sell them? Also, as far as I can tell Apple does a decent job of maintaining a stable price even with inflation. Laptops like the Macbook Air cost less than when they launched in 2008 and have stayed relatively the same $1000. Obviously phones are the outlier and their cost has seemingly skyrocketed with all manufacturers.