I have removed stuff from online in the past, and I definitely had and I expect to have failures in the future as well. However, it's not if I consider it a failure that gets me to remove it. It's whether I've completed the work or not.
If I started something and never finished it (meaning it's a half-finished story online) then I prefer to take it down. Simply because I wouldn't want someone to find it, start reading it, and maybe even like it, only to discover it's not finished and the story leaves them hanging. I hate when that happens, and I don't want to do it to anyone else.
If I have the whole story completed, then I will leave it up there. Even if it's "bad". Someone might like it and it is part of my journey, how I hopefully improved over time by creating.
It's also why recently I started uploading stuff that I have completed only. Yes, it will take a few months for everything to be available to the reader (it's in episodes) but I have actually written the whole thing and I'm already working on something else in the background.
But I had uploaded half stories in the past that I never completed, and those I have removed.