The people who are giving Microsoft difficulty here are the people who distinguish purchase types based on price. If they're going to spend $500 or more on a thing, that thing represents a significant investment, and they have always received 20-50 years of durability from significant investments in the past. Washers, cars, tractors, refrigerators, houses, all those things are expensive, but they last a long time. Even a color TV from the 1970s is still good enough for many of them.
You say "people shouldn't keep computer upgrade cycles to the same timing as vehicle or appliance upgrade cycles", but why is that true? All the rest of their experience is that "expensive things should last 20+ years" (even though they know that occasionally requires a roll of duct tape.) I see that as the root of the problem Microsoft has created here. Microsoft agrees with you on that assumption, but practical viewpoints of the world do not.
You and I know that security problems, reliability problems, media incompatibilities, speed incompatibilities, and all those things make keeping up with technology important, at least for people who are focused on the technology, but we have to consider that most of this equipment is now owned by people who aren't focused on the tech.
And we really can't reach them, either. If we use technical terms like "buffer overruns", we'll be ignored. If we say "upgrade or they'll steal your credit cards" they'll say "so I won't buy online, or I'll pay cash at the store, or I don't have a credit card anyway." If we say "it's too slow, or it's too limited, or the screen is low res" they'll say "it's good enough for me." And if we say "new computers are cheap these days", they'll say "I can't even afford to fill my car with gas." They are probably already feeling the pinch of not enough disk space, or ancient browsers unable to display their favorite web sites, but they simply can't afford an upgrade now or in the immediate future. Filling the gas tank helps them get to their paychecks, and food and rent are simply more important than upgrading their computers.
These people expect to get 20+ years out of their computers. It's our problem to live with them, viruses and all; it's not their problem that they have old gear.