The issue here is more complicated than just a lack of long term RCTs. It's that we're talking about psychological acclimation within individuals. Given that people's lives change so much, even within an RCT design it's not clear how you get an actual comparison of "effectiveness" from year 0 to year 4.
> t's not clear how you get an actual comparison of "effectiveness" from year 0 to year 4.
You'd probably need a few different measures of attention/executive function and you'd need to counterbalance them across people to prevent habituation.
Given that the regulatory bodies don't require studies like this, it's unlikely to ever happen.
