I was having this discussion with my husband yesterday funnily enough.
I had a date with a man shortly before I met DH. He was a nice man, intelligent, funny, and he'd just gone back to working in a supermarket after his business failed. He knew exactly where he'd gone wrong and had every intention of rebuilding, and at a different time in my life I might have gone for it and made his dream my dream and been a cheerleader.
However, the point I was at was that I'd dated a lot of men who were at that "fixer upper" stage, made a lot of sacrifices, and then when they were fixed up they fucked off. Either that or they expected the pattern to continue, with me doing all the emotional labour and tolerating the lack of input from him whilst he was busy "building", rather than being ready to switch things up so that I could chase my own dreams. I wanted someone who was ready now, not someone I had to build.
Having said that, all relationships require building together. My husband and I both had reasonable jobs and lives before we met, but we were living in HMOs and not exactly thriving. Since then, we've both changed careers, taken pay cuts, been unemployed, started again, and the other has had to pick up the slack.