Market cap for publicly traded corporations is still a good measure of value since there are laws, regulations, public disclosures, etc. ensuring they're equall

Market cap for publicly traded corporations is still a good measure of value since there are laws, regulations, public disclosures, etc. ensuring they're equally measured to a degree. If I paid $50000 for a cowry shell and said the market cap of cowry shells is more than MasterCard then there's a few problems...