Somewhere after 40, wisdom kicks in and starts refactoring how you work. When viewed from the vantage point of a 20-something, it seems there aren't many 40-something programmers around them, or the ones they do see are not dancing to the same tune they are, so the naive conclusion is that something cognitively negative happened to them. It's actually something cognitively positive. Could be that the 40-somethings have learned to protect their time, pay far lower taxes and make the same money outside of the corporate rigamarole, or could be that they're the boss' boss. What they are likely not is in the same place, doing the same thing in the same way as a 20-something. For me, it was both, but the former definitely gave me the time and space of mind to enjoy learning new tech again (and discard most of it), and work with new people locked into delivering good product instead of locked into rituals. Burnout is a good signal that it's time to let wisdom in a little.