They could still use d20, but instead of d20 + mods vs. DC, it would have to be Skill value + mods vs d20 roll under. But WotC wanted a fully unified task resolution system so here we are.
Hot take but I don't think it really matters much.
The problem with DnD is, and always has been, the scaling. Skill based games like Savage Worlds (and I assume CoC) don't have the problem of constantly inflating numbers. For an easier example, HP. SW doesn't have many ways to increase max HP, and even then you rarely go above a 6 (from a starting point of 3). A PC having 10hp is fine, but when he has 100hp, then you run into problems where a guy with a dagger can never kill anybody unless he stands there stabbing for five minutes of game time.
In skill terms. If talking that bouncer into letting enter was a dc12 at any level, then it would make sense. The problem is it's trivial for a mid level player to have +12 to the roll.
This is problem I've had with my PF2 campaign.
@Ghostse plan of PF2 killteam seems to working for the final leg. It doesn't help the rogue can't fail to lockpick any door, simply because RAW the stupid DC treadmil doesn't account for players that are through.
I've been doing prep for future campaigns. One idea I had was to make a setting like Dinotopia. I don't know if dinosaurs would talk like this setting, but having them as beasts of burden all over the place could be a fun twist on the usual medieval fantasy tropes. It could also make low level vermin and undead adventures more fun too. Instead of the usual bears, wolves, rats, and skeletons, I'm thinking small dinosaurs, giant insects, and zombie dinosaurs could work, even if they have the same or similar stat blocks. ...or it could be really dumb and I shouldn't do it. Not sure.
I'm also tempted to go the other direction and go all in on dragons, orcs, and other elemental DnD stuff.
I guess that explains it, but still seems incredibly fucking weird.
Yes, but also no.
If it's true that DnD is basically done. FLGS are no longer allowing games to played there, and said shops are switching to gunpla and funko pops in the wake of Hasbro/WotCs collapse, it makes sense. I didn't think it would be this quick or abrupt though. Like others said, I've not looked for dice in a while.
I could also talk about how FLGS are losing business in the long run by eliminating the third space and putting that burden on customers, but I don't know if that's something people here want to discuss.