TLOU Part 1 and Ghostwire Tokyo are also current gen exclusives for this year.
It's easier to develop for last gen and this gen than it was to develop for last gen and the gen before, meaning some devs are going to chase the larger install base to maximize sales
Also it can't be understated how the pandemic fucked everything up both from a game dev standpoint and from available consoles which limits the potential userbase of games being released. Sony in particular was aiming to come out swinging VERY hard with the PS5. They had an absolutely batshit insane 2020 with first party and console exclusive content to both see the PS4 off and introduce the PS5:
Then for 2021 they had intended to keep that momentum going with the following planned lineup:
The pandemic completely threw 2021 out of whack not only for Sony, but everyone across the board as studios had to adapt to a work from home workflow. As a result many projects got pushed back even further. We likely would've had far more current gen only titles release this year without the pandemic delays, but not much anyone could've done about that. Forspoken got pushed out of this year, but given its original release date it's possible it could've released in 2021 if the pandemic hadn't happened. FF16 very well could've launched this year as well instead of next Summer.
Plus the PSVR2 and its launch lineup are another group of games that will include current gen only content like Horizon Call of the Mountain. It's still within the realm of possibility that will drop this year, but more likely is it'll release early next year.
Look at the above 2021 lineup Sony had intended to have. Now realize that we would've been balls deep into the originally planned 2022 lineup, whatever that was, which certainly would've included plenty more current gen exclusives. So yeah, the pandemic really screwed things over...what can ya do.