I don't think your argument and analogy makes sense. Simplicity is not only valuable when an owner himself needs to repair the truck.
It's valuable when your truck breaks down in a middle of nowhere, and the closest official repair shop is hundreds of miles away, whereas there might be an "okay" level independent mechanic every 20 miles or less (the actual distance is not the point, the point is that an "okay" mechanic will be probably 10-50x more common).
Simplicity is also valuable with missing parts. Sure, the sophisticated solution is better in terms of performance, electronics, and whatnot, but it might take weeks to receive a part (even before COVID), because the shop doesn't have it and have to be ordered from China. Compare this with simple parts that you can again find in many old trucks and even smaller towns, making it much easier to replace.
Just to put it in coding analogy: if my business needs a website, or a landing page, I'm not going to hire a team of former Googlers and ask them to write a performant backend framework in Rust and invent a new frontend framework. I'm going to ask my uncle who is a hobby designer and can set me up a static site/WordPress in a day. I'm not trying to "justify poor engineering", I just prefer simplicity and the "poor engineering" approach gets my problem solved in one tenth of the time. Who is doing poor engineering now?
Also, coming back to the trucks. There don't need to be poor engineering from either side. Maybe the different requirements just caused trucks evolve in different directions?
It's valuable when your truck breaks down in a middle of nowhere, and the closest official repair shop is hundreds of miles away, whereas there might be an "okay" level independent mechanic every 20 miles or less (the actual distance is not the point, the point is that an "okay" mechanic will be probably 10-50x more common).
Simplicity is also valuable with missing parts. Sure, the sophisticated solution is better in terms of performance, electronics, and whatnot, but it might take weeks to receive a part (even before COVID), because the shop doesn't have it and have to be ordered from China. Compare this with simple parts that you can again find in many old trucks and even smaller towns, making it much easier to replace.
Just to put it in coding analogy: if my business needs a website, or a landing page, I'm not going to hire a team of former Googlers and ask them to write a performant backend framework in Rust and invent a new frontend framework. I'm going to ask my uncle who is a hobby designer and can set me up a static site/WordPress in a day. I'm not trying to "justify poor engineering", I just prefer simplicity and the "poor engineering" approach gets my problem solved in one tenth of the time. Who is doing poor engineering now?
Also, coming back to the trucks. There don't need to be poor engineering from either side. Maybe the different requirements just caused trucks evolve in different directions?