But the decline in holding periods predates app driven gamification. Lots of resources suggest this trend has been in place since the 1960s, I've linked to one below.

I believe the trend for shorter holding periods has has accelerated with the emergence of the internet, because now large number of people are convinced they can trade. When in reality all they are doing is feeding Wall Street (says and ex-Wall Streeter).

Overall though I agree gamification is dangerous. I don’t use an App when I buy stocks (I’m too security conscious) but have seen videos of the crap Robinhood, et al do to hook some people. Amazing.

https://topforeignstocks.com/2020/08/04/average-holding-period-for-u-s-stocks-is-just-5-1-2-months-in-2020/