Yes, the I believe the sum of fiat deposited on bitfinex, bittrex, huobi,... is close to that amount. I even see people from high school "investing" in crypto now.
It's really not hard to believe when you consider how many millions of people are on these exchanges. Binance touts 3 million users, and has 425,819,642 tethers. 141$ average a user is completely believable.