The largest US company in 1929 had revenues of about $1.5bn - roughly $30bn in 2023 dollars, which wouldn't even put it in the Fortune 100 today. Walmart today has revenues of about $600bn, which is roughly equivalent to 6x the top 50 companies in the US in 1929 combined!
It's mind-blowing to me that economics is still using these ridiculously old, flawed models whose assumptions are less true than ever. To me, econ 101 should be teaching how irrational consumers and lawmakers are, what state capture is, monopoly-seeking behaviours as the primary modern driver of profit growth, etc...