Interesting question, when I started investing I assumed that you could buy and sell shares whenever you wanted as it’s all digital. I was surprised that a digital purchasing system still had trading hours of 9 to 5, seemed a bit old fashioned. If I want to buy something off Amazon, I can buy it at any time of the day.
I guess it comes from trading floor guys having to have a reasonable working day. Personally, it would be better for me if markets operated 24/7 as I could research a stock and then buy it knowing exactly what price I would get if it’s 9pm in the evening or something.
Crypto is obviously newer, but trades 24/7/365 - always on. FX also trades 24 hours a day, presumably because it’s needed in order for businesses to trade.
I would guess that at some point the stock market(s) will go 24/7. It will suck for people who are on the trading floor or who professionally trade 9 to 5, but I think there will be some benefits to markets being open all the time. New information can be acted on instantly, instead of having to wait 12 hours or a full weekend, which in theory will make transfer of money and allocation of resources more efficient.