While reading the article, the now-less-common business of vacuum and TV repair came to mind. I imagine it's easier than ever to repair vacuums, with improved tools and free internet repositories of schematics. But I only know of one store still doing this within 5 miles of my house. I haven't asked former vacuum repairmen, but my guess as to the reasons:

1) Labor costs go up with inflation

2) Rent goes up

3) New vacuum prices go down

At some point in the past, the downward line of vacuum price crossed over the upward line of repair cost. That's when this profession cratered.

Cars may have a while until that price point hits. But the quoted mechanic's suggestion that engineers optimize for simpler repairs instead of simpler production may be something similar. If simpler production makes the price of a new car $X cheaper, but increases the labor cost of repairs over the car's lifetime by $Y, there could be a time when X > Y.