Simple as this:
If you work as an automotive tech or auto mechanic (whatever they call em these days) and you need a tool or tools, then the Snap-On guy comes to the shop. Comes to you, at work, and have specialty tools available that no one else would sell in a store. You typically don't have the time to go drive all over town looking for a specific tool for a specific job or to replace a broken tool. That is the service that the tool trucks offer above other tool brands. That is the advantage. That is what you pay for.
Sure there are other equally high quality brands and makers of tools out there. Others may ferociously disagree, but I find many other tools from NAPA, S-K, PROTO, Craftsman, Lisle, Channellock, Ingersoll Rand, Blackhawk, Williams, etc to be every bit as good as Snap-On, but none of those other tools will be delivered to you at your job the way Snap-On, Matco, or Mac will. You have to see it for the advantage they offer the techs.