Why would a new infinite runner be something anyone would actually want to play, instead of the hundreds of already existing infinite runners, unless there's a good addition to the core mechanics? How long did you actually want to play it yourself?

What makes or breaks just about any indie game is a brilliant core loop, or on the other end of the spectrum a novel "feeling" / aesthetic. Latter especially visible in the horror genre. Then after the original, there's the tail of variants that can do pretty well for the next 6 months of so, and it's exhausted, which is the part AI affects the most as of now.

There's countless examples of indie games crafted with care over multiple years, with great looking (but sort of bland) graphics, that have not done well.

Further, even before AI, a lot of people whose games didn't make it, did not at all have a grasp on what counts as a finished and well crafted game. Same applies to music. It's clearer in sports where (for example) the insanity of a marathon ran in 2:00-2:10 is easy for all to see.