Doujin circle Outside announced that Cosmo Dreamer, their first commercially, internationally-published STG, has sold a combined 5,000 copies across Steam and Switch—even some of the indie devs out there might be wondering if that's an especially notable number, given that the STG genre is sometimes perceived to have some sort of outsized cache within vintage game circles, but I can assure you that any indie/doujin STG that breaks a thousand copies sold is standing far, far ahead of the pack.
That said, there's a mostly-separate, mostly-silent ecosystem for euroshmups and other broadly shooty games the "real" STG community has deemed unworthy of attention that's happily bubbling along, and I do think it ought to be given more attention, if for no other reason than it's worth figuring out who's buying these games and why, and whether there's anything the creators of more conventional/arcade-rooted games should be doing to court them... when the ceiling is already this low, any little raise is going to be hugely beneficial.