Car USB ports are generally only for smartphones, which is the #1 computing platform in the world.
That’s really the crux of my point. USB-C is the “winner” because it’s ubiquitous in the smartphone and tablet world (especially now with full adoption from Apple underway).
Cars are also a piece of technology that does a frat job representing the lowest common denominator of the average consumer’s relationship with technology. If your brand new $2,500 MacBook Pro doesn’t have a CD player, that doesn’t mean the CD is dead. It’s an expensive early adopter’s device. But if your brand new Toyota Corolla base model doesn’t have a CD player, that means it’s DEAD.
There’s also the answer to the question “what’s the most likely cable I have on me?” If you have an Android or Apple phone from the past 5 years you don’t have any rectangular USB-A cable with you in your travel bag.
I would also argue that the average person has very little practical use for USB for a lot of its data transfer capabilities anymore. The average person who owns a laptop probably never plugs in anything to the port besides things they are charging or maybe a mouse dongle.
It’s expected that your car (and most people’s cars) are older, but what I’m saying is that the fact that someone buying a new car doesn’t get USB-A pretty much shows us that it’s not long for this world if not dead already.
Sure, my desktop still has plenty of USB-A ports since space is not at a premium and nerdy custom builders demand them. But if you buy a desktop computer from Apple it doesn’t have any, and PC OEMs like HP and Dell won’t be far behind.
The only thing I’ve used the USB ports on my desktop for are mouse dongles and a fingerprint scanner. Basically, ~$20 disposable tech that would work perfectly fine as a USB-C version. My keyboard has already made the switch to USB-C and my mouse charges with USB-C as well, and I bought these items multiple years ago.