Or..........
No matter how good the covers, how skilled the editing, the right format,the length or number of words, or whether it's "well written" or not - if the story isn't any good, if it doesn't grip the "gatekeeper", if it isn't original enough, or is the usual formulaic stuff that we do see in "self-published" work, then no commercial, or "good" publisher is going to wrap their arms around anyone involved with it.
Whether they are "indie" or not.
Remember, they either need to make money, or back stuff that maintains, or improves, their reputation, or that they like or respect.
If they think it'll sell, they'll take it.
The idea that the publishers gather in dark rooms and agree not to touch any "indie" author is....... unlikely, shall we say.
[And is the definition of "indie" that it's their first work, an ebook, or that they have sworn never to be tainted by a mainstream publisher.....