[ig1]

It doesn't make sense to evaluate historic seed stage valuation based on current valuation. Any angel investment looks like a bad deal retrospectively for a billion dollar company on that basis.

Investments need to be evaluated on the basis of the valuation at time of investment.

Certainly there are many companies who could raise money at higher valuations elsewhere who go through YC, but almost none of them could raise at a >$15m valuation (YC doesn't typically invest in post-A companies).