As an entrepreneur, growing a "runt" company is basically wasting your talent, and that of anyone else you have working for you. Your own skillset, and all the company's other assets, are locked away doing something that's not making anyone--especially you!--nearly as much money as you could if you tossed the current company out and rolled the dice again. If a larger company was responsible for the project you were managing, they'd shut it down and move you to something else where you could make them more money (see: Google Reader.)
In economic theory, this is why layoffs and recessions are good: they kill companies that were just getting by, and release the human capital "stored up" there to move to newer, brighter ventures.
I mean, it's fine if all you really wanted was a lifestyle business--but lifestyle businesses don't take investment.
By comparison, creating a company that will both make money and do good in the world is not nearly as efficient for actually doing good in the world.
Further reading:
* http://lesswrong.com/lw/65/money_the_unit_of_caring/
* http://lesswrong.com/lw/6z/purchase_fuzzies_and_utilons_sepa...
Are you saying that if my "meaning" is derived from, say, extending the human lifespan, then starting a company that tries to do that--and fails (because extending the human lifespan is a public good nobody wants to pay for)--is more meaningful than creating some kind of SocialMobileLocal juggernaut, and then spending the money it generates to fix the problem for real?
To me, that just sounds like impatience and an unwillingness to look at the big picture. A startup itself can be a schlep, to achieve something greater.
So VCs learn to respect people who are determined, and truly believe in what they are doing. The entrepreneurs who stick it out are therefore demonstrating that they are people the VCs should respect, even though the relationship is not working out well for anyone. On top of that working together through shared hardships tend to create bonds - and these are people who work together with the VCs through shared hardships.
Moving on to the second half of the equation, what about the VC? It may be tempting to quickly abandon all of your failures. But doing so means making worse returns than you could otherwise. Furthermore developing a reputation for abandoning too easily hurts your reputation as a VC, and therefore hurts your ability to find good future deals. So a VC is stuck with their bad decisions as well as their good.
And a final fact for you. The bigger the investment that you take, the harder it becomes to win big. There are many reasons for this. One is that too much money makes people complacent. Another is that there are more potential markets out there that are worth $50 million than are worth $250 million, so it is more likely that someone you invested $2 million at a $10 million valuation can earn 5x returns than someone you invested $10 million at a $50 million valuation can. Therefore VCs are on the lookout for opportunities that are big enough to be worth their time, but want to invest as little as they can in each one.
You'd just fire everyone, walk away, and hope to hit bigger next time? Your investors are unlikely to agree that this is the best way to use your talents...