Bullshit.
Yes, some of the most popular games in recent times are multiplayer, and originally Xbox was more popular in MP games (outside some exceptions lke FIFA) due to having better online and trophies, plus some great and very successful first party MP games like Halo or Gears and the CoD marketing deal.
At the second half of PS3 (or even early PS4) days Sony did catch up with the quality of the online plus adding features like trophies and game agnostic voice chat and getting the CoD marketing for them. Sony also signed many MP games as exclusives during the PS4 gen such many fighting games, or more stuff like MiHoyo, Rocket League or Fall Guys plus partnering with top MP devs of titles like GTA Online, Fortnite, Destiny etc. in different deals.
In the first party side, they were very successful with single player but not with multiplayer, so they kept focusing on single player. But the general PS/console (not 1st party only) list of top games got more focused on multiplayer (and GaaS) titles more and more over time, so at some point in the PS4 gen Sony decided that had to make a big push on MP and GaaS, particularly on shooters, and they started the current Sony push we're seeing of games like Destiny 2, Firewall Ultra, Helldivers 2, Concord, Marathon, etc. plus non-shooters like GT and MLB.
Sony is pushing to be top tier with their 1st party (also including 2nd and acquired) catalog not only in SP AAA games, but also in MP & GaaS. Plus they are trying to cover top selling genres better with their fist party to depend less on 3rd party and to make more money for themselves. So this is why they're expanding in genres like shooters (with all these mentioned GaaS), action games or platformers. And well, also expanding their IPs beyond gaming to make more money and expand their fanbase outside their console.
From a year ago:
From to years ago: