Arrowhead was literally a small no name studio before Helldivers. From was a small no name studio before Dark Souls. Bad take.
How far back do you want to go? Arrowhead had Magicka and Helldivers 1 was in 2015.
Firesprite had The Persistence (71 on meta) before working on Horizon Vr. That's it. I know there's some old history with Psygnosis but Firesprite was a useless purchase. A publishing contract was enough.
In addition to Horizon CoM (79 MC), Persistence VR (the original version was for PSVR and got 78 MC), the non-VR The Persistence ports made later (75MC in the other platforms other than the one you mentioned), Firesprite also codeveloped Star Citizen, and for Sony codeveloped with Team Asobi small experimental projects like The Playroom, The Playroom VR or Run Sackboy Run.
Before that, most of their leads did work on Liverpool Studio (including XDEV, which was part of it), Evolution Studios and Bizarre Creations. Others in Supermassive, Lionhead or other AAA teams.
Between Magicka and Helldivers, Arrowhead developed The Showdown Effect (67 MC) and Gauntlet (68-71 MC).
Before Dark Souls From Soft had developed a few dozen of other popular niche games, specially in Japan or as PS exclusives, like the King's Field series, Armored Core, Otogi, Echo Night series, or titles like Ninja Blade, Enchanted Arms or Demon's Souls. Weren't super sellers and in most cases didn't have great reviews, but had certain popularity and prestige inside their niches before Dark Souls.
What I don't get is why this studio is so big yet hasn't release anything to justify it's size.
People here point out Insomniac but Firesprite is a far worse offender when it comes to size vs output.
Yes, you don't get that games aren't developed in 3 months and that teams need several years to develop their games.
Insomiac has been big and had 3-4 teams since generations ago, and Firesprite no, they did it recently.
Firesprite wasn't that big before, started to grow when they worked in The Persistence (first for PSVR, later ported to other platforms) and Star Citizen at the same time and later swapped Persistance with Horizon CoM, while they also started their (minimum) two other projects they were developing at the same time than Horizon CoM: a multiplayer game that featured on foot and vehicular combat and a dark horror adventure.
