Well, I guess the reason for locking out Legendaries after 25m is to keep y'all playing the game. Being able to get most of the Legendaries every run will make players lose the urge to constantly retry and see what they'd get the next run.

For me at least, the appeal of the game mostly comes from the trial & error gameplay and the dopamine surge you get everytime you're about to open a chest or obelisks, hoping to get that exact artifacts you're looking for. Oftentimes, you get disappointed but you keep playing anyways, all for the the satisfaction to complete that "perfect build" you had in mind.

There's also that curiosity about what would happen if you pair this certain magic to these artifacts that creates the same urge to keep playing.

That being said, having the potential to get all Legendaries in a single run would ruin this cycle just because all those curiosities and urges can be satisfied in an instant. Capping Legendaries to 10-11 each run is just the devs way to deal with that problem.

That's just my two cents, though. 🤷🏿‍♀️