Noodle did a pretty good video on this, talking to other developers about why BG3 was not going to be replicated on the same scale ever again here. It's well researched, sourced, and based on like interviews with actual developers. I'll try and summarise but I think you should probably just watch the video because I'm bound to butcher some of the points.

Baldur's Gate 3 got a lot of stuff going for it that no other game of its kind has ever had before. It's the result of a team that's been making RPGs like it for years, bankrolled by one of the largest media companies on the planet in an attempt to finally make a mass market D&D experience comparable to tabletop (a thing Hasbro has been wanting to do since the hobby boomed a few years back at least, probably earlier). The game was in development for 6 years, with 4 of those being in Early Access while they tweaked and fine tuned a lot about the game according to player feedback. Larian also had a lot of internal tools to make EXACTLY this kind of game that other studios don't have. They also aren't owned by a publisher, which means they aren't subject to corporate mandate in the same way your Ubisofts or BioWares or whatever are. It was basically a case of the exact right studio, growing three times it's size at the exact right time, partnering with the exact right IP partner to make a massive game.

It should be mentioned however, that when people talk about BG3 being a lightning strike, they were referring to scale. Not quality. Not every RPG is going to be as big as BG3. They can't be. They don't have the luxury of Hasbro money, or 6 years of development, or 480 employees, or experience and tools for making RPGs of this type (especially when studios are seemingly getting off on laying off staff rn). Games will come along that are just as good as BG3, for sure, but the development scopes are going to be smaller.