aren't most of these just direct copies of some other game that went famous? e.g. Dark Souls set a genre "souls-like", Stardew Valley copied an old game but we can say they started the resurgence or development of cozy management games...
the bit about testing what sells vs what you love is real too. we ended up testing three completely different positioning angles simultaneously with different audience segments, just to figure out which one actually sticks. feels less like art and more like running experiments, but honestly that's what keeps you from burning cash on the wrong audience for months.
the Beatles analogy in the post is interesting but i think the better framing for indie creators is: you need a tight feedback loop. not "make 600 things and hope 50 land," more like "ship, measure retention at day 7, iterate." the constraint of small budgets actually forces better product thinking imo.