There is reason to believe these cars can be sold in the lucrative metal export market, so it's not a total waste. Perhaps our old cars will help build the new chinese infrastructure.

I agree, it seems quite wasteful, but how wasteful remains to be seen.

Ideally, I think what you want is an upgradable car, like a jet fighter, that can maintain a single body and have replaceable components.

I don't think we'll ever get that though because consumers are too fickle, and there is no real benefit to the manufacturer.

Yes, even for cars with significant onboard user-oriented software systems (like the Prius) there is no upgrade path. It seems we are currently in the "early cellphone" phase, rather than the "iPhone" era where automotive software is concerned.

What is so upgradeable about the hardware in the iphone ?

Note my use of the word "software".

Yeah - the buying patterns of tech and cars are quite different. As you say, people don't buy a new car every eighteen months. Buying cars also involves a lot more intangibles than buying technology does, and costs a lot more.

There's also the whole system of buying (dealer networks with huge overheards), as well as the difference in how long it takes to bring something from concept to market (based on safety testing).