They are doing this because a rotten corpse doesn’t force them to compete, they can do whatever they want. If MS didn’t shit the bed with the Series X/S, Sony would be trying harder to please customers, or at least not actively screwing them (see also: 800 EUR PS5 Pro without disc drive or vertical stand).
Mostly it’s the lack of competition.
On one hand, regulators allowed big companies to become monopolies, so we don’t have a choice. Imagine if instagram and whatsapp were not part of facebook, how different social media would be? Or if bumble and hinge were competing with tinder, not just all being a part of match.com.
And on the other hand, we have examples like the console “war”, where Xbox messed up this generation so hard, that Sony now can do whatever they want.