The minimalism fad c. 2009-13ish opened up a marketing window for new shoes and new "technology" or the lack thereof, and therefore brands.
Something I know less about is the manufacturing process, which has surely has gotten substantially more efficient. I had Nike's first Flyknit lunars. Not long after, everyone could make basically the same thing. I would guess the manufacturing facilities might be available to launch new shoes. But it's also important to note that Hoka's real dominance in the hobby market has come after they got bought out by a larger company.
What I actually do find surprising is that generic shoes that are actually good haven't really come along in the same way other things have in other industries. Instead, for example, you have a Chinese company like 361 come along and seem an awful lot like Asics in initial designs, but now those things cost $130-200 like every other premium brand. It seems like the market would be wide open for someone to ripoff some new but not cutting edge foam and throw a decent upper on it and sell them for $60 instead of $120.