In many areas of the country, the car will rust long before you get to 175k miles. The car/truck market is not composed only of people who want to buy a car and keep it for 20 years until it falls apart. That’s a small segment of the market.
Car manufacturers sell what people want to buy. For most, the benefits of an auto transmission far outweigh considerations of what the transmission will do after 175k miles.
Afluenza.
From what I understand, cell phone usage has doomed manual transmissions in even high performance sports cars which have paddle shift automatic. People only have two hands, so one to steer, one to fiddle with the phone and none for the gearshift. Hands free via Bluetooth didn’t reverse the trend.