To provide a frustrating anecdote from the publisher's side: we'd love to heavily invest in launching new open access journals (which we do, but we'd love to do even more). The problem with launching a new journal (either subscription or OA) is that nobody will publish in it if it doesn't have an impact factor. Impact factor is controlled by a private, for-profit company (Clarivate) that's owned by a private equity firm. Getting an impact factor takes 3-5 years and also relies on the total crapshoot of what Clarivate decides to list or not list. So the prospect of launching a new OA journal is one where you are guaranteed to lose money for the first 3-5 years and then you have to put all your eggs in the impact factor basket, hope you get listed and receive an impact factor, and only after all that will academics choose your journal over any established legacy brand. And all this because at some point academia decided that they'd outsource academic career assessment to the magic number that is Impact Factor.
I also want to thank you and the other commenters for some good discourse here. This has been refreshing and I was only called an asshole once the whole time! But jokes aside, a sincere thanks :)