@yohane I dunno, there might be a fairly even split on the kind of people responsible for summoning of the heroes and what not. I've made a point of checking out a ton of isekai stuff because while a lot of them are pretty generic and possibly even boring, you do run into some decent ones but those always have so few chapters available... so hunt for more and more, y'know? If it was just summoned types it'd be easier to get a feel for the ratio, but there's also plenty of truck-kuns and other methods for the whole thing mixed in there so it's a bit harder to keep track.
I can also think of one example where the royalty that did the summoning are dicks card got played, but it turned out later on that the actual ruler had been absent at the time handling political shit and the the other members of the royal family there decided to cause trouble. They were not happy campers when the real ruler came back and put them in their places, but the main character was pretty gratified.
Does seem to be a universal constant to the genre that someone in the nobility or royal family (families, I guess, since some of these worlds have so many different countries) is a massive bastard, though. They're in the perfect position to cause drama for the main character after all.