The shittier real life is, the greater the appeal of escape.
Similarly, the popularity of the slow life and slice of life genres reflect a desire to escape the 24/7 daily grind.
Isekai, reincarnation, regression, dungeon appeared in real world exist in Manga, manhwa and manhua because that asian countries have people that high suicide and depression.
it kind of escapism to reality and with the world they have either changes with sudden appearance of dungeon, they able to remake their life (regression), reincarnated and transfer to another world or game ( their life suck in their country) slow life ( their jobs suck and stressed with constant grinding) .
that's why its popular because in reality,they wish it was true.
that why its always OP MC that get all best woman. because most of the reader are single man that nobody want and have ugly face and no talent.
they imagine themselves as the MC.