"Scaling DCs" is just math homework that leads to no mechanical change.
A "scaled world" plays into the fantasy of growing from a regular person into a great hero. Progressing from fighting goblins all the way up to fighting dragons is a pretty central part of DnD in every edition I've played. A game in which you start fighting goblins, play for a year, and are still fighting the same number of goblins sounds kinda boring.
I think most games don't have this level of decontextualization. In the tables I've been a part of, the party doesn't look at the three areas around them, see one has lvl 17 dragons, one has lvl 8 trolls, and the other has lvl 1 goblins, and pick where to go based on levels. The party has a goal or mission that they want to accomplish, and the challenges they face are appropriate to that goal.
At lower levels, these goals tend to be more modest, like tracking down a thief or fighting off some bandits. At higher levels, they become things like stopping ancient cults, or overthrowing a small nation. The "levels" of the encounter are just natural results of taking on more challenging tasks. Obviously a group of bandits is weaker than a standing army.