It all goes back to this.
In the 90s the SEC was pushing for integrated markets. As the market got more fair trading, became super popular. Everybody was a trader and some us even became full time traders. It was the conversation on the golf course and while drinking with friends. Then some of the established trading firms got smoked by internet stocks and they stepped away. The Nyse started to monkey around with its rules. (and then got bought out)
Since that time wall street spent the next decade buying off the sec and politicians and buying up exchanges and fracturing the markets so they could create structural edges.
As the market got fractured and the market itself less fair, the public stepped away.
It will be interesting to see how this resolves. Unfortunately I do not see any public figures saying we need to integrate the market to make it fair for investors.
+1 for all above