A properly protected door should last many years. One that we bought was not up to outside use, and failed. That manufacturer ended up purchased by a competitor, I think.
My experience: swan-neck kitchen taps all now seem to be quite different in design from one-another. To replace a washer, you have to dive under the sink, completely dismantle the tap, replace the washer, and re-assemble the tap. And the new taps start dripping after just a couple of years.
So you have to hire a plumber; and he'll probably work faster (i.e. lower charges) if he's fitting a new tap than repairing an old one. So you might as well order a new tap before you call the plumber out.
One can model their business around market rules. It just might not be as huge as you want.
But Instant Pot is the classic example of going broke because everyone bought exactly one of their products and never needed another (ignoring the three we have...)
Keep a perfunctory tidbit of the once great company chugging along to provide replacement parts, do some servicing, and sell new ones at a much reduced volume. Just enough to keep a handful of people employed at good wages and turn a miniscule profit.
I know it is heresy to suggest this kind of thing when our entire way of life is predicated on infinite growth, but our entire way of life is also grossly inefficient (not to mention inequitable) and we are facing ever more scarce resources on a planet with less and less carrying capacity for our wasteful and destructive tendencies.
Of course this is all just yelling at clouds, because billionaires and the people who service them cannot be made to think in these terms, else they wouldn't be where they are in the first place.
That's the expensive bit. That's a lot of machinery and tooling sitting around mostly doing nothing.
It is my understanding that when Instant Brands filled for bankruptcy, they weren't selling just the Instant Pot. It wasn't even the original Instant Pot company. They were selling a wide range of kitchen products. I don't think they went broke because people bought exactly one Instant Pot.
The story doesn't end here. Apparently, Instant Brands emerged from chapter 11 as Corelle Brands.
> They go broke or rely on an ever growing market, ie housing is always being built (most of your examples).
Wouldn't that mean those new houses have new families which want a new Instant Pot? In fact I can think of other situations: people moving, going to college, splitting some of their items in divorce, etc. Sure, it's not much but it's not like the demand grinds to a halt.