My point was more that you're citing an edge case to defend your argument, and I'm not sure comparisons with other types of products are fair.
There probably are still people out there using ancient PC and Mac hardware to do their day to day shenanigans, but as more and more of life depends on being online, using modern hardware and software reduces the friction of that dependency by large amounts.
Windows for Workgroups 3.11 and Windows NT 3.51, actually.
I agree that financial concerns are important, but again, since no budget was cited, I simply steered away from premium offerings due to cost, and budget offerings due to performance concerns. There's nothing worse thinking you've gotten a bargain and then being disappointed with the purchase because the computer underperforms in almost every way (slow CPU (e.g. Atom, Celeron, AMD APUs) and storage (i.e. eMMC rather than SSD) coupled with low RAM will make any version of Windows from the last 10 years sluggish, small storage provision will reduce capability, small low-resolution screen will cause problems, etc).
I'm personally unaware of significant issues, but that's not what's at stake here. Using XP-era hardware with the XP OS can lead to a myriad of potential problems, most notably the lack of security updates, but also things like shrinking driver support for newer accessories (your new printer doesn't work? Awwwwwww) and recovery liabilities (how can you rebuild your computer to working order from your install media when you can't download any updates to your drivers or system files?).
If we do want to keep going down the car comparison route, when the manufacturer (software vendor) issues a product recall due to a fault (software patch to correct security failure), do you just ignore it? No, because you want to be safe, so you return your car for repair under the terms of the recall (install the software patch to correct the vulnerability). When the manufacturer decides it's time to no longer manufacture parts or issue recalls because the model is too old and thus not economically viable to support (software is too old and has been replaced several times by newer versions), and a critical fault is discovered in the entire model range of that age, do you just keep plugging along hoping you won't crash due to that fault, potentially injuring others?
Granted, the physical risks of an XP machine becoming part of a botnet are not even in the same league as a car careening out of control, but why take the risk?
It's the same with Vista, and in 3 years time it will be the same with Windows 7. Personally, I always try to approach technology purchases with future proofing in mind. I can either purchase something now on the cheap which I may need to invest further in down the line to keep the system functional, or I can invest a smaller amount on top to get something that carries less risk of being obsoleted sooner.
In addition, Windows 10 has been unanimously hailed as Microsoft's best operating system. I know those inside the FOSS bubble don't get much exposure to Windows, either through circumstance or by choice, but it is impressive. It is performant, reliable and useful. Why select an operating system that will never receive a fundamental update ever again when a newer one is available that is still inside a featureset upgrade cycle, ensuring it will become more useful as time progresses?