The affordable part isn't a miracle or anything amazing, it's simply the product of huge economies of scale. If airplanes were made in the hundreds of millions per year, they'd be a lot cheaper too (still a lot more than cars because of the materials and labor costs).
But you're right about the reliability aspect: cars really are a lot more reliable than airplanes, in that they don't need lots of frequent maintenance. If you compare modern cars with cars from 50+ years ago, the difference is staggering. Ask your grandparents sometime about how long their cars lasted, and how much maintenance they needed. You can see it in old advertisements from those times: cars needing lubrication every 1k miles, for instance.
> If you compare modern cars with cars from 50+ years ago, the difference is staggering
This - even 30 years ago, if you were doing a 4 hour+ journey, there was a pretty decent chance your car would break down at some point. It would be on your mind. Nowadays, it’s really almost unheard of, to the point where people don’t even think about it.
But you're right about the reliability aspect: cars really are a lot more reliable than airplanes, in that they don't need lots of frequent maintenance. If you compare modern cars with cars from 50+ years ago, the difference is staggering. Ask your grandparents sometime about how long their cars lasted, and how much maintenance they needed. You can see it in old advertisements from those times: cars needing lubrication every 1k miles, for instance.