As somebody whose first book came out last month from a (very) small indie press... yeah. In trad publishing, once you've got an agent (not an insignificant step), you only have a handful of shots at the Big Five publishers with your manuscript. If they don't want it? It's small press or self-pub, and good luck getting your book above the sea of mediocrity.

The novel I've got out is urban fantasy, but what I _really_ want to get out there is the hard science fiction series entirely from the aliens' points of view... which is very much not a fit with the current zeitgeist. Because that's unlikely to be a blockbuster, if I ever want to see it in print, I'll probably have to do it myself, with a proportionately diminished chance of finding readers.

(And all this is one reason why writers have day jobs. I'll be pleasantly surprised if my novel income hits even 1% of my tech job salary this year.)