I recommend actually listening to some authors.

The “gatekeeping” back in the days before ebooks was infinitely worse than it is now. These days? Basically anyone who can fill out a webform can publish a kindle book. And other stores aren’t much harder. And those ebooks can be sold indefinitely.

Contrast that with needing to find a publisher who is willing to allocate some of their limited production time to you. And then hope that Borders et al are willing to put you on the shelf. And then realize that you are never getting another penny for that book because the first MMPB run ran out and you aren’t getting a second because you didn’t sell enough to justify it.