The point (ok, a point) is that in the 5e play-loop, you don't set a DC until after the player has declared an action, and you've judged the outcome uncertain.
It is a way around it. The hypothetical DM hypothetically narrates hypothetical failure for the hypothetical peasant, success for the masterful character heavily invested in the skill, and calls for checks from some of the folks in-between, with a DC set by his judgement of how likely that character is to succeed at that task under those circumstances. You can't say, well, I made that DC 18 check, but a peasant could've done it, because it might not have been a DC 18 check for the peasant, it might've been narrated failure.