I thought the same as you until I got into a shop. I work from 7 to usually 7 and my tools are my paycheck. I don't get a chance to drive 30 min to lowes/sears/hf to warranty. I also don't have time for a tool to fail, not that snap on doesn't it just fails less in my experience. If I need something I call my driver and he brings it to me. If he doesn't have it I price it on amazon and prime ship it if it is a lesser used tool. Daily numerous use tools I prefer snap on. I wouldn't be able to justify snap on if I weren't a professional that requires a certain level of tool performance day in day out. I do buy proto as often as possible as they have never let me down either. My toolbox is a hodgepodge of hand me downs and top boxes on roll carts lol, tools pay bills boxes don't, until I can afford a good one lolol.
+1, and a few more things to add:
Having the option to finance $50 weekly on revolving truck account instead of throwing $500 down at once makes life a lot easier to budget, especially if you're living almost paycheque to paycheque (not unusual for new mechanics). I pay less for tools every month on the truck than I used to in big box stores hunting the lowest sale price.
Most importantly I get the full range of sizes I need, whereas the big box stores will sell you an incomplete set. I lost a 10mm stubby GearWrench, went to 4 CanadianTires on the way to work, and not one of them stock my missing wrench by singles. Lose a socket? "Sorry we don't carry that in singles, you're gonna have to buy the whole set.". See the trend here?
The real kicker is the BOGO deals on the flyers. Buy a socket set, get a free ratchet. Buy a box, get a free scanner. Buy the SAE and get the metric free, yadda yadda. You'd be stupid to think people actually pay full retail for every piece on a box full of SnapOns.