Stock Market
JMO Non institutional/retail are still a school of minnows in shark infested waters. One of the biggest change has been the adoption of options strategies and the delta hedging required by Market Makers to remain delta neutral. Look at what happens when the reddit apes get going on AMC/GME, etc and gamma squeeze the market makers using options.
Things done years ago get traders in big trouble mostly because of the trading range of the market. 30 years ago, a decent days range on the NQ futures 50 points, an outlier was a 100 point day. Now those ranges can occur can happen in 15 minutes or less. Range on the NQ is in the 300+ points per day. One NQ contract in that hi-lo range = 6K+ in potential loss or profit.