Xbox at least will release Halo and Forza this year.
I don't think this is a good reason to get an xbox... at least not compared to Horizon 2 and the few other exclusive PS5 games (the series s/x had their minor stuff too).
The hardware inside both consoles is similar enough that it should not matter much, however the series X has a more traditional look to it and the PS5 looks like a piece of modern art, a big one.
The libraries are mostly their backward compatibility with some enhanced titles (which xbox does have more and a generally better approach to enhancing old games).
It seems many xbox "exclusives" are coming to PlayStation anyway, at least on the Bethesda camp.
Sony upcoming exclusive content is a known quantity (if you liked them in the past chances are you will like them again)... While MS bought a ton of studios, so they are bound to release something notable, which they have not made in a long long time, but again, it seems they are going to release some of that output on PS machines, so I'm not sure how much of an argument it is to get their hardware.
So they launched this thing on November 2020 but they won't have a single fucking game worth buying until holiday 2022. That's unbelievable to me.
You were not alive early in the PS3 and PS4 lifespan? Sony has "downtimes" in their release schedule, this has always been the case and I have no reason to believe it will end one day, unless you count their baseball games that are released on a yearly basis.
This is why buying a PS5 is a known quantity, if you like Sony exclusives they will show up and you'll be happy to play the next God of War or whatever it is they come up with.... if you don't care for them, then third party titles is what you have to look at (obviously if Forza Horizon is what you are looking for the PS5 is not the place for you and the discussion is not really worth having, just like if you want to play Grand Tourismo)