[monoideism]

So what happens in your method when you hit a major unforeseen issue, as frequently happens in a project? If your prior 2 projects went by without a problem, then you'll still be sitting on a bad estimate.

Yes, after time, this should start to even out with your method, but who keeps the same team or even stays in the same job for more than 3-4 major projects? It's fairly unusual these days. Yes, I know there are some senior devs that stay at the same job for 5 or even 10 years, but their team, and even the company's hiring standards, are likely to chance significantly during that time.

That said, it is an intriguing idea, and one that bears more study. I'm not yet convinced but I may try it out.