(This is in response to the grandparent: "VCs aren't preternaturally biased in favor of lightweight companies, but the people who are doing heavyweight stuff don't have the time to become "real founders.")
Also, here's the difference for real founders vs. the rest of us. Real founders get alternatives put in front of them when their ideas are rejected-- EIR gigs to pay the bills, spots in portfolio companies. The rest of us get zilch; spent months with no income and nothing to show for it. Real Founder social status doesn't mean that bad ideas get funded, but it does mean you don't have to deal with the extreme income risk associated with startups for non-Real Founders-- a risk that stops making sense to take after age 25.