There has never been a time when the working class retired at 55, except because of physical disability.
That's simply untrue, and I aslo know of many in said class who have personally told me that their bodies are beginning to give out and they're looking for other things to do.
There are probably SOME trades that are not SUPER physically demanding ... such as to be an electrician, though that can vary as well, but most of the others are physically very tough jobs, from plumbing to carpentry, etc. Yes, you can still do it to a point, but it's simply inevitable that you SLOW down, you start getting back or knee problems. Good luck trying to do one of those jobs if you've thrown your back out. AND you're much less vigorous and your abilities are diminished. Why do you think that professional athletes are considered washed up in their early 40s? And these are men whose very lives revolve around working out and keeping in shape, even in the various roles that are less demanding, like you play baseball as a DH or play first base, where you don't have to exert yourself all that much, or as a catcher. After their early 40s or so, their reflexes start to go, as do their batting averages, as perhaps their eyesite begins to fade, and so on and so forth. That's just a fact. So, just like with programming, NOBODY is going to want a guy who's closing in on 60 compared to taking someone in his 20s or even 30s. After decades of experience, you could be a supervisor, a mentor to others, etc. ... but you'd have diminished role in the actual physical aspects of the job, and somebody just getting into those trades when going on 60 could never assume that type of role, where he'd be the wise sage that others would look up to and consult with. You'd be a newbie at 60. They hire newbies when they're young precisely to utlize their youth, energy, and their vigor ... but then as those attributes and qualities diminish, their experience and knowledge increase. 60-year-old newbie is pretty much a non-starter.