People aren’t talking about money itself, they’re talking about hedge funds and prop shops and traders, which didn’t exist prior to the 70s and even Wall Street traders weren’t trading pure securities until the early 1900s (it was slaves and real shares before then) Economy worked just fine without the quants, and ever since trading has been a major segment of Wall Street they’ve completely crashed the markets three times and had to be bailed out by the fed (1929, 1973, and 2008). If you take the capital allocation justification at face value they suck at it. They’re losers underwritten by the government not winners smartly allocating capital.