What makes you say the value of their contribution is minor? Is there some public basis for that sort of claim to be found elsewhere?
This has nothing to do with "product", though.
Memestocks are down ~80%. Crypto prices down ~70%. Volumes are down even more in many segments... >97% for NFTs.
Just because Coinbase was at one time valued almost 10x what it is now, doesn't mean that was the correct value - and "product" ruined it.
So he really extracted more like 2% of the value of the operations of company itself.
This is his legacy
Excluding the stock performance entirely, they've released no particularly successful or even interesting products under his tenure.
He comes from Google where he worked on ads and shopping, so honestly that tracks pretty well. Google (not Alphabet) hasn't done anything interesting or innovative in a long time now either.