Self publishing isn't so much a matter of time. In fact, a mainstream publisher might take more of your time than you would take yourself. What you don't get in self-publishing are the things that mainstream publishers do to make a book successful: edit it and market it. Though it's fair to say many authors don't think they do enough of either anymore. You also don't get their investment. The initial and per-copy costs are yours. Self-publishing houses that do print-on-demand will link you into Amazon, etc., but that won't sell many, or any, books. Successful self-publishers fill their car trunks with copies and get out and push them.
Self-publishing is a tough road, for a simple reason: there are no gatekeepers, and most self-published work is utter and unmitigated crap. Some is not, and some is really extraordinary, but people know that the odds of getting drek are high.