Makes total sense. I guess the hope is that the people that are in those professions (that they can't do later in life) are making a good deal to set back for when they get older, other than just banking on SS benefits. But obviously that doesn't happen for a vast majority of trade workers.
Perhaps the other hope is that if you are in a trade for decades and decades, at some point you then have the opportunity to move up in the ranks of management and/or ownership, e.i. less manual labor intensive positions, still in the trade.