You keep throwing our complexity without knowing what it means.
Bethesda has a certain style of game, but RDR2’s handling of missions and NPCs is vastly more impressive AND complex. Plenty have multiple ways to tackle missions. This isn’t something unique
No it isn't. RDR2 gets constantly shat on for being on-rails and having outdated mission design that basically boils down to "chase this guy, stop this train, shoot this thing."
That you tried to say that freakin' Zelda's NPCs are similar to those of Bethesda games proves how ill-informed you are. It's not even the same planet.
'without knowing what it means" you must be fucking joking. You're the dude who seriously argued Zelda is similar to Bethesda games in terms of NPCs. Clearly, you didn't play their games for any significant length of time, so why argue?
Specific to this thread, how is the complexity a limiting factor in the engine allowing a 60 fps mode?
For one, there could be a 60fps mode later on, who knows? Redfall will supposedly get a 60fps mode. For two, you've been told but keep playing dumb. The fact that the game is 30fps but 4K suggests a CPU bottleneck, pointing to the game logic and all the stuff the CPU has to do to run the game properly. This includes the thousands of things a character can do, their schedules, stats (that you hilariously tried to dismiss as being irrelevant), equipment, what faction they belong to, their pathfinding, etc. That plus the thousands upon thousands of objects littering the world that you can interact with and that also have physical properties such as mass, volume, etc. You enter a cave and there are two mage factions consisting of necromancers, fire mages, lightning mages, and others, blasting different spells all at once while summoning creatures and raising their dead comrades or turning invisible or maybe they simply run away because they're afraid. That's the kind of stuff that can happen in TES and it's not even scripted. Shit can get out of whack when multiple random events interfere with one another.
And no, not Zelda, not RDR, not Horizon, not GTA, not Elden Ring, not AC, none of the open world games you will name does that like TES or come even close.
There's a reason their games are so buggy; the sheer numbers of interacting variables is mind-boggling.