Having a top-tier VC invest in you is an outside signal of credibility in recruiting, PR, marketing, and other areas. VCs who are competing for the best deals are creating new methods of adding value outside of "just a check." This can't be replaced by crowdfunding, at least not soon.

Alternatively, take a look at a lot of the hardware/product projects on Kickstarter. Those startups are using Kickstarter as a platform to show their idea is wanted and credible. So then the VCs who passed on the risky venture come in later after the idea is validated to a certain extent. They might not see the same upside but they're also taking on less risk.