Brake pads? A garage can lift my car up, take all four wheels off with a pneumatic driver, and be mostly done in a few minutes; for me, that's a hand-jack lift of each corner of the car one at a time, with a hand and foot lug wrench to remove and re-fit 20 wheel nuts, then a trip to dispose of the brake pads, and several hours.
Framing it as "ignorance" and "voluntarily incompetent" is incorrect, I don't reject the knowledge of brake pad changing, I desire to avoid the work of brake pad changing. It doesn't need doing often, I don't have the tools and experience to do a good, quick, job (pneumatic wheel nut removers, or a car lift). I already have to get my car inspected annually (UK), and that's a perfect time for a garage to change things. Worse, if I screw something up by being inexperienced, I'm in trouble - I can't drive my car to a garage, and a tow would cost more than the work. Assuming I can afford it and am not on a tight budget, then were's the compelling reason to do it?
> improve their independence
An illusion. I can't legally run a car without a garage doing an annual inspection, I can't make my own brake pads. I don't become more independent by removing and replacing 20 wheel nuts.
> [improve their] knowledge
Brake pads need changing every ~24,000 miles, that's every 2 years of average mileage, or ~25 times you will use this knowledge in your adult motoring life. Rough numbers. (Electric cars with regenerative braking will reduce wear on brake discs and pads). Is that a priority thing to learn? The best available thing to learn?
But my point is not that it's a bad trade, my point is that framing it as "the only imaginable reason is wilful ignorance" is little more than a putdown, and it's wrong. There are other reasons. You're selling the Heinlein-ian "if you can't do Everything yourself, then you're not a Real Man(tm)" worldview with a slightly different wrapper on it.