Older devs probably don't use SO as much, because they are the one who built the great tools.
They built the techology stackoverflow was based upon, they didn't need SO when they were developing in the 80s, 90s. they probably don't need it now.
Well, even if there weren't a problem with age bias I would expect the median to be skewed lower. The details indicate that not all respondents are professionals. This could include youths, still in secondary school who are learning to program.
But if the age distribution of people is such that the median age of humans were 27, it shouldn't concern us that the median age of this population of survey respondents is 27. I don't know what the human population distribution is but I took a quick peek at the US census bureau and it seems to indicate much more young people than older. I suppose that shouldn't really be surprising.
That caught my eye as well so I googled past surveys to see how the results have shifted. What was more interesting to me is the 2016 distribution is very comparable to the 2013 distribution. But then again this survey hasn't been going on for that long.
https://docs.google.com/spreadsheets/d/16C6ZeNSvd-qIg45J9E-v...
Nope. A lot of people that identify as 'developer' move on to other roles such as team lead or architect or, if they're lucky, retire before they hit 40. There's also the bias of stack overflow's users, of course; I can imagine that experienced devs visit SO less and thus never saw the survery (I know I didn't, and I still occasionally visit it)
Those numbers are for the average SO user, not the average developer. Developers who've been developing for 20 years before SO showed up on the scene are less likely to make SO part of their development routine and less likely to fill out surveys about current programming trends.
In the past, gender discrepancy was justified just as glibly as ageism is now. People said almost exactly the same nonsense then: women just got married, they moved to other fields, this particular poll is biased (never mind they all show the same trend), they quit to raise children. In the ageism case, someone even ludicrously suggested retirement before 40 accounts for a significant percentage
Ageism is indeed a very serious problem and the same personality types that didn't want to fix bias problems in the past are resisting addressing the age problem with equal vigor today.