I wonder if lonely shut-in recluse losers are the main demographic for comics and anime in Japan, because they really love using them as a protagonist in their work. It's more perplexing, because they rarely have the character really confront what it was that made them that way, or they just play it up as a joke; why not inspire these people to do better with their lives rather than just indulging in fantasies?
Heck, even many of the characters who are not shut-in recluses seem to show many tells that they were made for such a demographic of people to still associate with (being too focused on games, having no friends, hating their life, general depression, perpetual virgins, etc).
...That is a fair point, but there also is the tiniest nugget of substance to scenario stereotypically used in such isekai stories (and probably by accident, not by design).
What keeps someone like a hikikomori capable of living like they do is having the means to do so. If you take a social/family safety net, housing, food, etc. out of the equation - they just sit there and eventually die.
Which causes them to force to change if they don't want to die by very virtue of being thrown into a (literal) new world without anything. Of course, it's put on super easy mode 98% of the time because they get cheat powers or abilities of some nature which makes it multitudes easier for them than a regular Earthling or inhabitant of the new world their on. But, unless they're suicidal, they're going to try and survive.
...Which when you stop and think of it, there has to be entire graveyards in some of these worlds with the corpses of Earthly humans that were thrown into a new world and
didn't survive - for whatever reasons.