If people survived ShB leveling dungeons there's no reason they couldn't survive EW content if it was harder. Do people become worse upon finishing ShB? Games are supposed to become harder or at least stagnate after a point, not become grossly easier.

The issue with the EW dungeons is that they hit like wet noodles while restricting how much you pull too much.

Holminster Switch or Mt. Gulg for example were great because players had the option to push themselves and go for big, painful pulls. Not having this option make EW dungeons an absolute bore.
"Dungeons are boring" but they don't have to be.