I don't consider open world design that's effectively linear due to massive level differences to be particularly good design either. It feels very artificial for there to be an area of level 1 goblins to be right next to an area of level 9 million demons.
The problem with Piranha Bytes world design is that it often feels very arbitrary. ELEX being the latest example, you have areas that are logically challenging/impossible for a new character, but then you also have areas blockaded by challenging enemies that are just sort of there for no good reason (Why is there a Slugbeast guarding a sword a new player can't use right outside Goliet? Why is there a Slime Drakon right outside of the Domed City?). As you said, it's effectively linear, or is linear at least for the first 10 hours or some such. People complain about New Vegas' open world for similar reasons, since the player is effectively forced to complete that Goodsprings->Primm->Novac->Boulder City circuit before they get to New Vegas itself and the game actually opens up, although experienced players can circumvent this. It's just a difference in the development priorities, really.
That very linearity is what I am talking about. It forces you to go down a certain path, where the mobs are tailored to your expected level at that point in the game if you follow that linear path. That is level scaling.
What the idiots don't get is that level scaling is vital to a RPG so that new players are not overwhelmed by something they can never defeat and then rage quit the game. While it is trendy for Codexian arrogant fuckheads to claim that any RPG that fucks over newbies as "good design" because "it doesn't scale to your level", it is actually very bad design from a business point of view.
What I do not agree with (which I have said several times now) is level scaling using the same mobs but with either more betterer equipment or bigger, betterer stats. You want your players to feel that their characters are getting stronger, not static. Players want to see their toon graduate from rats to orcs to bears to dragons. They don't want to see their toons fight rat, stronger rat, even stronger rat, and rats that can take down dragons. Both are forms of level scaling.