> Implicit here is the claim that giant companies do hilariously dumb things a greater fraction of times than small companies, but I have seen absolutely zero evidence of that.

I don't think that's necessarily what is implied. Small companies make decisions with many orders of magnitude less resources applied to making those decisions, so we expect the outcomes to be significantly worse on average. If Google spends 100,000 times the resources on its decisions but the outcome is only 10x better than the output of a random small company, that is notable.