Honestly, you have a point. At one point there was a proposal for a "Linux Standard Base", but none of the distros really cared (they had their special sauce), so it withered. If Linux app devs could target "LSB-2020" or something, it could be similar to Windows devs targeting a particular Windows version. Flatpak is basically a work-around to the distributions.

(Note that Windows also does vitalization for compatibility reasons.)

On another level, maybe it's just "in the name". Windows lets you run your GUI windowing programs, and that all keeps working. GNU/Linux lets you run 1990 base industry standard API programs, all that keeps working, but for anything else, all bets are off.