Because there is no particularly easy term to describe games like Days Gone, Last of Us and Horizon that all share the same similar tone, gameplay loop, bleak theme and human drama story focus. If you really don't like one of them you're not likely to like any of the others. And then you just get the "but what about Spiderman!" response, as if another open world game is a perfect answer because it has a comic book superhero instead.
See, this counter argument is probably one of the most annoying because it completely ignores how incredibly varied the Playstation catalogue used to be, how weak most of the PS4 years were in comparison, and how the PS4's launch lineup itself wasn't representitive of Sony's output for the rest of the generation.
Like wow, a racing simulator, three platformers, another Souls and some mega budget open world titles - literally the few genres that Sony hasn't ever stopped putting out entries into. It's a far cry from the days of Parappa, Dark Cloud, Singstar, Buzz, Modnation, Ico, Sly Cooper, Folklore, Motorstorm, Ape Escape, Pixeljunk, Vib Ribbon, Twisted Metal, Wipeout, Eyepet, Tokyo Jungle etc. that people are talking about when they say Sony's old output had far more variety.