Aren't the vast majority of Windows revenues from new PC sales and volume licensing?

Both would continue if Windows was "perfect" feature-wise and only security updates were provided going forward.

> if Windows was "perfect" feature-wise and only security updates were provided going forward.

Therefore the kernel is secure, assuming spherical cows are used in the bubble memory of the return stack.

One possibility is from the huge surplus that they collected when they initially sold the software.

It seems to ultimately boil down to software becoming more expensive to sell, especially when it will be used in critical situations.

But that's handled by the contract at the point of sale. One Windows XP with N years of support for $ money.

Legally, they are covered.

Sure, there is this specific situation where Microsoft probably isn't on the hook for anything.

But there is also the more abstract problem of how hospitals and the like go about using computers.