Repairing computers isn't presented as a selling point because it's not a selling point. Nobody likes having to gently pry open their computer and poke around at its insides, it's a daunting prospect, and even if you do everything right there's still a chance that you broke your computer. Why is that a good thing? How is that better than going to a retail store, handing over your laptop, and then getting it back fresh as a daisy in a couple days?
Do you think people also threw bitchfits when cars stopped being easily fixed by amateurs?