It's not an entirely unreasonable heuristic. The supply of startup pitches is vastly greater than the demand for them. Investors have to filter somehow. Getting a first meeting with any VC is pretty easy, even for someone with no connections whatsoever. There are hundreds of possible paths you can take to get that intro. It's not a big stretch to assume that any entrepreneur with a good chance of success should be able to clear that low hurdle.

Building a successful startup is 1,000 times harder than hustling your way into a VC meeting. If you can't do the latter, it's pretty likely you won't be able to do the former.