I'd say both would be in a worse position? Shortages were not as bad when they launched in late 2020...potentially this had an impact on the price and maybe they have somewhat locked in their price with suppliers (just guessing here).
Luanching end of 2021 would definitely mean higher cost of hardware, and I doubt they would be able to produce anything significantly faster.
Games wise I think Sony are okay, im not a fan with their choice of games to produce (Demons Souls remake, Miles Morales, Sackboy) but the games were there. MS might have benefitted from a year delay with regards to games, but it seems like they still wont have anything meaningful in 2021...let alone 2020. So that would have been an even longer delay if the idea was to wait for big exclusives.
Gamepass and performance improvements (backward compat and system) seems to be the main selling point of Series X and its still sold relative well. Also releasing last year lines up perfectly with the Xbox strategy - get as many people on gamepass as possible.







