Let's ignore any and all context that might have made BG3 an exception. Famous IP is something the frostpunk devs don't really have. They've got a great start, but 50 plus years of books to pull from, it has none.
I can't speak for frostpunk 2, but frostpunk 1 was like a roguelike city simulator that teased some lore while beating your face in with disaster after disaster. It was novel for a bit, but i had zero interest in repeating that experience with frost punk 2.
I think narrative driven story rich games are great, but I don't think frostpunk fits into that category. Frost punk was a rogue-like with a theme.
https://www.youtube.com/watch?v=3kwK3m261Mw
Even when the stupendium song came out for frostpunk 2, i watched it with interest, but didn't really want to play the game again.
One of the big problems with NARRATIVE games, where there is only one narrative - is replayability. BG3 is a master-class in branching narrative and evolving worlds, more akin to a D&D session with a really, really, really, well prepared GM - so people play it over and over... and their friends seem them playing it, and it encourages them to try it.
I don't think i've ever seen any of my friends playing frostpunk
Even if you want to play a single player narrative game, there is no urgency to buy it, it is 100% perfect for patient gamers to wishlist and wait for a deep discount, there is no social urgency to play with friends like hell divers 2.
That is with an assumption that both games are equally well received. I was actually pretty hyped for frost punk 2 after finishing the first game but was disappointed when the review came in. It was overall considered as a downgrade or not as good as the first game and the ratings show that as well. Same situation with the forest but I think sons of forest will also improve with time but as a patient gamer, I can wait and get a better discount anyway.
My problem is that I'm absolutely not interested in a story driven wannabe city sim. Same issue I had with that space station game. It just turns those games into a puzzle game that you need to solve in order for you to reach its end, but that's absolutely not why I play games like this. I'd be way more interested in Frostpunk if it was an open ended game that focuses more on its building and simulation instead of a story. Be more dynamic and varied. We saw very successful survival based city builders like Banished before. Granted, Banished was also fairly simple, but that was also afaik a one man project - and despite that still managed to gain a lot of popularity and replay value. Of course the community making mods helped with that too.
I think the devs here just fell into the "more of the same" trap with their game.
For BG3 I kinda hope to see some more persistent & dynamic open world stuff too from the modders, now that the mod tools are kinda unlocked to their full potential.