Earlier quoted context omitted.
All the consoles go through the same thing every time there's a new generation. The consoles have never been backwards compatible, each generation invalidates your previous library. And they always begin with tiny libraries. Here we are in 2020 and only now have Sony and Microsoft begun talking about backwards compatibility in future console generations.
Never is a strong word. The initial version of the PS2 had dedicated hardware to be fully compatible with PS1 games.
* GameCube to Wii
* Game Boy to Game Boy Color to Game Boy Advance
* Also features a case of backwards compatibility on behalf of games too. A lot of GBC games would run in a Gameboy in black and white
* Nintendo DS to 3DS
* PS2 to launch PS3
* (Announced) Xbox one to Xbox Series X