Yeah, this is the tip of the iceberg. K-pop is somewhat popular in the west, so it's a little easier to find out, but there's a whole thing of needing to be "available" to the fanbase to feed on that parasocial relationship, but not available enough that it encourages stalkers. The animated film "Perfect Blue" is a sort of mash-up of Hitchcock-style horror and Idol culture. This also impacts streamers these days, as you've got companies like Cover (Hololive) and AnyColor (Nijisanji) that run talent agencies for VTubers, and a very similar type of parasocial relationship exists there too. Cover in particular has been courting successful independent streamers, and it is definitely variable how the agencies treat the talent.
Another aspect to consider here is how for many of them, this is how they make ends meet while they are pretty young. Last couple years of high school, or during college, and then they age out in their 20s and switch to a different career.
But the whole thing with Depp and Heard is kinda an offshoot of similar mentality. Fans investing themselves into celebrities who don't even know they exist and taking sides on the drama and making an even bigger deal of it. It's still a parasocial interaction, but it plays out differently due to the cultural differences. It's also the case that advertising in the US feeds on similar ideas: "If you buy this product, you can attract a gal like me." It's just not quite the same level as feeding the idea that fans can get the idol themselves.