Question about the $6,000 floor quote that took me 11 hours to figure out

So I run a small flooring crew here in Cincinnati and a while back I bid a job at $6,000 for a basement floor that was supposed to be a simple glue down vinyl plank. I get there on day one, pull the old carpet, and the slab is so uneven that a marble rolls across it like it's a skate ramp, and I mean it moved a good 4 feet. I figured I'd just pour some leveler, no big deal, but the homeowner did not want to pay extra and I already gave my number. So I spent basically 11 hours over 3 visits trying to figure out if I should eat the cost, walk away, or find a cheaper way to float it out. My buddy keeps saying you always walk, the number is the number, and a bad job follows you around town forever. But the other side of me says you eat it once, do it right, and that lady tells every neighbor on her street about the guy who stuck with it. So where do you draw the line, does a quote you already gave count as a promise, or is that just business? I want to hear what you would have done. What was your worst one of these jobs and did you eat it or walk?