Some of us are interested in a good story and immersive universe. This has none of that, the story is like the least of any From game with faceless characters only shown in their mechs, it creates a distance, no investment. So just purely gameplay, then you gotta ask how many fans of mech gameplay are there? And this is between people who like a challenge, since its a hard game, which again lowers your potential buyers.
So people who are into mechs and very hard games. INSANELY NICHE. Since most young people are into gaas/mobile stuff and traditional core games are carried by millenials, not sure how many are into the niche genre of mechs and hard games.