Well, yes and no. 'Deprecate' is more often used in programming, and discussing features of a programming language, or API set.
Maybe my use of the word wasn't the best, but the example was appropriate. Apple doesn't have to support *every feature* of *every OS* in perpetuity. Imagine the mess... And, yes, why would anyone upgrade from System 7, if it were still supported. Some wouldn't really need it at all, yet others would want more features, but that's a bad analogy, taken to extreme.
Apple did it for cost, and it was money they felt they shouldn't have to spend. Were they wrong to do it? Hmm... If you broke up with a girlfriend/boyfriend, and you were paying for their cable, would you want to keep paying for that cable, months after breaking up? Would they, or should they, be able to sue you to keep paying for their cable? Hmm...