I'd agree with this. Very few fans are Perfect Blue style obsessive creeps, or ones so deluded to think that their oshi personally loves them. This is true for JP and EN fandom alike. Most people throwing thousands of dollars per month at their oshi don't actually think that said vtuber is their girlfriend or something.
However, vtube fans in general are prone to forming deep levels of emotional attachment to vtubers, and that leads to simps. This is partially by design. When most people compare vtubers to idols they think only in terms of surface-level aspects - songs, outfit, unit themes, etc - but the real similarity is how agencies in both markets cultivate their fans.
Japanese idols often aren't that good at singing, dancing, acting, etc when they debut. Frankly some of them never become that good, especially compared to their hyper-polished counterparts from Korea. The appeal in Japanese idols is often not that they are the best at what they do, however. Instead, idol industry relies on fans who like the story aspect of idols - the experience of seeing them grow from newbies to stars and celebrating their milestones and events along the way. It's like seeing an anime character go through their character arc, except in real life, and as you watch your favourite idol progress through their career, you become emotionally invested in their growth. It almost becomes as if their success is your success, emotionally speaking. It's not a coincidence that idols typically enter the industry young and progress through this arc until they become adults before leaving the industry for something else. That point in a person's life coincides with the idea of a coming-of-age character story.
Vtubing, both intentionally and unintentionally, replicates much of this experience. This is why milestones like 3d debuts, first lives, and subscription counts (100k, 200k, etc) are such a big deal in the fandom, and why people love the idea of vtubers being "broken" girls who are discovered by their agency and then uplifted by the fans. Again, it's like an anime story, but "real." It makes vtubers more approachable and relatable than some hyper-polished actor or celebrity. It's why fans get together and work on projects for their oshi's birthday and anniversary or whatnot, something that does not happen nearly to the same extent for non-vtuber youtube content creators, even those with more subs than vtubers.
I should say that while I may come off as cynical - and I am, to an extent - I don't think this model isn't inherently bad or evil. At the end of the day vtubing is a business for agencies and a career for many vtubers. Marketing is important. And for some vtubers, following this model probably isn't even intentional most of the time. The result of it, though, is that we get simps, people who have deep emotional connections to vtubers they will likely never speak to, let alone meet, in their lives. These simps are an intentional part of the system.
