No, it's most definitely a choice. You can make any engine run at 60 FPS if you sacrifice something else for it. The RE engine runs beautiful games at 60 FPS, but they had to make all sorts of sacrifices to fidelity to get World Tour in Street Fighter 6 to run at all, let alone at 60 FPS on current gen consoles.

that asthmatic engine they’ve been dragging since Morrowind

I don't believe that's true at all, though. At least by Wikipedia, Morrowind was NetImmerse, Oblivion was Gamebryo (modified Havok), and Skyrim was Creation. And I remember in the announcements for Skyrim that they remade the engine for the game. And Starfield is an updated engine, Creation 2

https://en.m.wikipedia.org/wiki/Creation_Engine for more

Call of Duty still runs on the Quake 3 engine, if we go off of the logic people uncharitably use for Bethesda's games specifically.