People tend to forget that DLSS use physical, hardware taking, space on the material board.
This mean that if you don't use DLSS, a portion of the GPU you paid for is unused.
Whenever you use, or not use, FSR... you can always reach the theoretical 100% of your GPU.
I'd argue 7000s series and up since they actually have AI cores on the board. Any sort of AI crap on the previous generations is such a hassle that I doubt they'll support them.
I couldn't get a good understanding if AI will only be used for Frame Generation (which I'm not so enthusiastic about, with its latency and quality issues) or for upscaling too (that I'm quite a fan of).