The relevant difference between cars and computers in this case is what, exactly? They are both high-tech, require a lot of resources to manufacture, and can remain useful over a long period of time.

They are dramatically different industries.

Let me reiterate, what computer manufacturer provides Apple’s level of support for more than 7 years?

Plenty, when you pay enterprise support contracts, but Apple doesn't do enterprise actually.

Please provide some examples, because the few programs I’ve found (enterprise-level and not cheap, example: Dell ProSupport Plus) all end at a max of 5 years after purchase date.

That would be breaking NDAs.

Google is out of the Chromebook hardware market, but they provides ChromeOS updates for 10 years on current machines.

https://support.google.com/chrome/a/answer/6220366?hl=en