>Startups all look different, so a good VC can be better than a bad VC if they just know which differences to look for.

I don't think this is an obvious claim. There's no strong evidence that VCs are capable of differentiating good startups from bad.

VCs manage to turn a profit?

My understanding is VCs (as an industry) fail to beat the S&P500 returns, so no, they don't turn a profit.

And thats their job to predict which startup will make the most money or produce most value. In capable of doing shows their weakness, so anti-portfolio is quite relevant IMHO.