I think it's just that the VC model is predicated on finding that fraction of a percent of investments that gives you astronomical ROI as opposed to more conservative investors seeking lower returns more often (the type of person who would invest in a restaurant just to get a check every month). They are willing to get nothing back a majority of the time while the more conservative investor would probably be bankrupt if even 50% of his investments netted a total loss of investment.

Chipotle, even after getting hammered in the recent past, has a market cap of 15.5 billion dollars. It's rare, but it's possible.

In fairness, that's because VC culture is a parasite on normal society.

They could (and do), but the prospect is longer-term and riskier, which makes it far less appealing.