IDK.....You lost me in the first sentence "Most have it pretty good(six or near figures)".
That just isn't true and is a company driven false narrative.
The vast majority do nowhere near that well and the minority that do, have invested many years to get there.
I made 6 figures for quite a few years and made even more about $1k(take home)(more) per week in sleepers. Even though I had "invested" many years at UPS, I was still only # 30 in feeders(because of the go to the bottom system). I always bid 50+ hour week jobs etc. I was willing and able to work....so I did.
False narrative......UPS'ers are the highest paid in the industry. Bottom of the barrel 45 hour jobs will pay about $80K. I made that for many years. I know most folks can only dream of such pay. Not to mention bennies.
A part-timer would have your perspective.
UPS has always been considered a "good job" by the public. Pay wise.