Judging by the number of answers I see which were valid and good answers in 2011 and are horrendously outdated now, it's not just grown up, it's grown long in the tooth.
That said there's usually an answer further down the page with a more up to date solution, it's just not the accepted or most popular one.
I would wager the majority of C++ users "in the field" are using 11 and below and haven't had a good opportunity to switch to 14 or 17 yet. As such, answers that seem outdated to you may be a good fit for the majority. It's sort of like how any native answers automatically float higher than boost answers - why is this? Because most c++ users are not using boost and have no interest in using boost.
If the idea is to be the "wikipedia of programming", I wonder if "votes" are enough. Should there be an active initiative to prune stupid/bad questions? Revisit old answers?