I've been in shops all my life and finally ending with my own. I saw more Snap-On and Mac than anything followed by Craftsman. HF was a very very small %. Many techs break tools everyday. I've only seen a handful of techs that didn't have back up tools in their boxes. Plus my Snap-On man and my Mac man would deliver a special tool I needed by the end of the business day. If you are a pro tech you can't stop working to go to Sears to replace a ratchet or other tool mid job.
Now on the other hand in the past few years since my shop closed more new techs have hit the market. I see more HF, Kobalt and Craftsman boxes in shops than I ever have. Im seeing more and more auto techs leaving the trade due to low wages and shortage of work.
I think you need to examine the time frame you are discussing.
From the early 80's to 2006 we were in a boom time, and boxes kept getting larger, swank tools where all the rage and even starting guys had a huge chest of Truck tools.
Times have changed and are changing even more.
The days of the Truck guys giving support like you are describing seem long ago now. Many shops around here (1,000,000+ local population) don't see a truck of any kind in weeks.
Many trucks have about zero stock, everything is back order, I mean, everything.
In business first thing to be trimmed is inventory, always that way in recessions. Heck, Fry's electronic, where in the boom times you had to almost climb over inventory, has trimmed it till they have started spreading the gondolas to make them look less empty.
Also, before the mid 2000's tools from places like HF were pretty darn junky.
Now the hand tools and much of the air tools, etc. are superior to most the products sold in the 80's.
The tool cartels are pretty much busted.
The days of an SK socket selling for 2 hours pay at Minimum wage (1975) are long, long gone.
As to mechanics breaking tools everyday, yeah, I know one of those. Now that he's starving he doesn't break as many tools... and the word 'careful' has lately entered his vocabulary.
He would NEVER use a 1/2 inch ratchet, just the 3/8, and who cared what broke. Now that it takes a week to three weeks to get a new socket, or a ratchet, and now that the truck guy argues every warranty, he uses the proper tool for the job. And does a better job.
Times have changed.