Main reason is that despite being in bottom 3 currently there is at least 3 worse squads in PL (Bournemouth, Southampton, Leeds & Forest).
At worse there's at least 8 squads who are very similar currently. I do think, on paper, West Ham, Leicester and Wolves have the better squads out of those at the bottom of the league. They probably have the 3 most experienced, and arguably best, managers out of the bottom 8. That doesn't mean they won't get relegated but over the course of a season I think they have enough to stay up.
I think the other 5 teams are similar. Palace may be the joker here. They are definitely a more talented squad but they do seem to have fragile confidence currently. They could be the team that drops over the 2nd half of the season.