The tech on the truck needs to weigh the increase in time required to complete a "full" set of tools (no such thing), versus the increased productivity, lower downtime, whatever else from a more expensive option. Additionally the guy buying 2 types of gearwrench wrenches, will have more options than the guy with one set of Snap On, Proto, Wright, whoever. So that's a factor a lot of people don't consider starting out, largely IMO because they don't entirely understand the tool ecosystem and their options, or the scope of the work and what may be required.
I've posted many times, starting out for the 1st few years, the trucks don't make all that much sense. Especially now that you can buy a nice and complete metric sockets set anywhere that have good metal and a nice high tooth ratchet that will last. Even back in the 2010s when I started getting a wrench set complete to 24mm, local, no skips, wasn't that easy. Maybe you could go to Grainger or similar, but you couldn't afford Proto starting out any more than Snap on. Now the internet has them everywhere and more retailers have these larger tools or at least single wrenches.
IMO the new tech needs to maximize volume of "decent" stuff to take on more work and secure their career. As money is earned and an attrition of tools begins, we evaluate other options. I must have bought every specialty tool, most of my sockets, wrenches, hammers - everything from Harbor Freight related to my work that I could get. It's all I could afford, I didn't much beyond 30k a year slinging tires and dumping oil, hoping to advance with no training and little help. And as things failed, or weren't that good, I at least had money previously earned to reinvest. Without the money from the jobs already done, there is no money for the replacement tool or the upgraded tool or the next tool. It's nice to just buy the best right off the bat. Many cannot afford that. I also throttle expectations of new people - the drop out rate in mechanics is massive. Within 10 years? You probably lose at least 75% who enter. So while throwing down a quick 50k will buy you nice tools which will last for years, if they leave the industry it's a loser as an investment. Spend a little, make some money, make sure you're in it and double down.
Something I don't think got mentioned yet - some of those amazon tools ARE the premium top of the line option. Like the Lisle fan clutch tool, who else even makes one? It's the defacto on the market, every tool truck has a set in stock. So just because it came from amazon doesn't mean it's not a great tool with a great profit potential, or even the best on the market.