"There's a market price for all the different options"
The market isn't efficient though, because there isn't enough information (tho your comment and the GP are helping increase that). It may very well be that there are worse deals at some points.
Believe me, I know how inefficient the market is. There are certainly overpriced and underpriced startups. But his claim requires more than an inefficient market. He's saying that startups in a certain phase are consistently overpriced. That I've seen no evidence of.
The market isn't efficient though, because there isn't enough information (tho your comment and the GP are helping increase that). It may very well be that there are worse deals at some points.