I am usually entertained by Microsoft events like this, but it is only because my BS meter is fully turned on. How many of these games will also come to XB1? Will they overhype something no one cares about like "Minecraft in 4k"? Will it have some gimmick like watching TV with a Kinect? Will they invite cirque du soleil again and turn their show into a literal circus?
Basically, once you subtract off all of the BS, then how much actual content will they have? I'm even going to be super generous to them this time. They get half credit for any game that also comes to PS5 just as long as it doesn't come to a gen 8 system. I'll even give them full credit for a Series X exclusive even if the game also comes to PC. Games must also give a release date of 2021 or sooner to get any credit. Again, I'm setting the bar really low this time, but usually Microsoft finds a way to limbo under my expectations.
If you think that majority of games announced at PS5 event won't also have PS4 version, you are gonna get disappointed. Devs are not stupid to leave 100m+ userbase behind, so PS4 will be supported for a really long time. Way longer than XB1 will.
X1 will be supported for a long time to come also because of backwards compatibility and Game Pass.