We have not received permission from Manueljf to share the quoted post.
This isn't a 'real thing' though.
Players will just always take on whatever they can do.
What you're talking about is a high 'skill cap' for PvE encounters, which DOES stress players because most players are average
by definition
.
Many posters have talked about wanting a very challenging world, but what ends up happening is that the game must give bigger rewards to those who can meet the challenges, and the average player gets left behind, complains, then often leaves.
For many, the question is 'why play if I can't keep up AND it's very hard?'. Single player games, you 'try until you succeed and then you feel good'. There's no one 'getting ahead of you because you aren't so skilled yet.