Well, due to the chip shortage PS5 is still scarce out in the market and I think it's the main reason why we still have cross-gen big budget AAA titles despite we're 2 years in to the next gen. Almost every important game both released PS4 and PS5; like GoW: Ragnarök, FFVII:R, The Callisto Protocol, Resident Evil: Village etc. We can't move on and reach the full potential of next gen because of that. The only games I remember in the previous gen that released cross-gen was MGSV:TPP and Persona 5 (I don't count annual titles such as Fifa, PES, AC or CoD because cross-gen is mainly their thing as a tradition).

Hence, this is why I think you're right, we might have a more long lifespan for current gen. We may have PS6 like 2028 or 2029.