How come you are in 50s and still have to code?
a) You like to code b) You are good at coding c) You suck at anything else
It seems you think good quant developer would move on to better things after a while. However, most quant analyst/modeler I know have to do most of the coding themselves.
The ultimate goal of most quant developer is to develop a “viable” trading strategy; convince the money people in charge of it’s value; and convince them to make you in charge of trading it. Hopefully by the time it stops working you’ve developed something else or made enough money to give you some flexibility in deciding what to do next. In all cases you’re expected to program your models and test them. I am not sure why I can’t do that by the time I’m 50, even though I hope I won’t have to do it. The only problem I would have is to test and program other people models.