Of course, market cap v. GDP is a stupid comparison: market cap is valued in dollars, GDP in dollars/year. It’s a bit like marvelling that the distance from Kansas City to Wichita in miles is bigger than the speed limit on the Kansas Turnpike in miles/hour.
Let me know when a company’s market cap exceeds the total value of all capital in a developed country, or a company’s annual revenues exceed a developed country’s GDP and I’ll be impressed.
I’d accept a comparison of GDP to revenue, but market cap is silly.