Here in my city, computer science is still a relatively "young" degree started at most 20-30 years ago. So most of the "senior programmers" here are at most 40 years old. I have friends in London in their mid 40s are earning decent salaries by working for investment banks on various financial products. Some of them don't want to get "promoted" as project managers because they still have the passion in coding and they are probably making more money by coding.

However, when you get older, you might loss creativity and might not unable to pick up new languages or frameworsk as fast as those who are decades younger than us. For those who are unwilling or unable to be migrated to be project managers. What should be the mentally retirement age?