When was the last time you played? Because rather recently they added a literal Oblivion scale to the game, meaning all zones now scale with the player's level.
The levels scale but the zones themselves are still different difficulties. So if you're level 1 and wander into an end-game area things will likely be level 50 or so. If you're level 50 and go there they'd be like 80-100 or something. Having played before and after that patch I can say the level scaling actually makes a lot more sense functionally in the game given the size of the map and it being open world. For a long time places like The Forest were pointless to go to if you were high level because everything would be level 5. It also balanced out some of the lower level progression by making sure the zones were the correct relative challenge.
I wouldn't compare the level scaling to Oblivion because as far as I'm aware Oblivion scales pretty much indefinitely while FO76 I think only scales up to 100-120 or so (weapons in game don't go beyond level 50 and neither do perks - there are no additional stats/hp/damage gains after 50). You can still be an invincible killing machine and things won't scale up to a point where all your perk/equipment purchases feel like you're level 5.