Maybe they become bartenders, or pursue a dream of professional dancing...

Really? My family is full of 50+ year old engineers and I can't think of any engineers that I know that changed careers as they got older. Sure some of them may have taken on more management responsibilities as they got older, but non of them left engineering.

If you're thinking of only the 50+ engineers you know, of course those ones haven't changed careers. You'd have to think of some 50+ year old actors or chefs you know and find out if they used to be engineers.

Fair point. Let me rephrase. Of everybody I know how's done a late career switch, engineers are extremely underrepresented, to the point I can't think of any. The closet I can come up with is a surveyor, which I suppose counts an engineer in some places.

The most common educational backgrounds to lead to a later life career switch in my limited observation is either teaching or banking/finance.

Is that broadly true, or are you thinking of software engineers?

Have any sources for this? My experiences say the complete opposite.

Is this actually true for engineers in general, or just software/electrical engineers?

But even so, this amount of skew is way higher than could be explained by that alone.