Between the prices of PS5 and Series X, this makes sense.
PS4 and Xbox One are easier to develop for than PS3/360, PS2/Xbox, etc. There will likely be an eventual end of mid and AAA games on PS4 and Xbox One (it's already declining), but I'm thinking it will take until Xbox 5 and PS6 launch.
With scalability and other factors, Crossgen makes more sense than ever.
Lifetime Sales Predictions
Switch: 161 million (was 73 million, then 96 million, then 113 million, then 125 million, then 144 million, then 151 million, then 156 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 48 million (was 60 million, then 67 million, then 57 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima