The road atlas that I use doesn't need a software update, it *does* go out of date, but only has fast as the maps on your sat nav
Plus I get to decide the route...
More seriously (I know that sat-nats do have their uses) - I'm really quite surprised that TomTom etc are still managing to make money out of SatNav boxes, given that most people (not me, but...) have phones that do the same thing 'for free' (of course it's not free, but...).
I can see an 'offline/traditional' sat-nav would be a lot of use in, say, the highlands where the mobile coverage would make using google maps (etc) impossible to use, but I fear that the amount of time that anyone will keep making 'self-contained' sat-navs will be limited...
All I would say about updates on devices/planned obsolescence etc is this (and I've worked in these kind of areas):
some of the things you've mentioned above are (as you suspect) just mechanisms to make you spend more money
some of the things are not desired by the companies involved but it's not econmical for them to support the old product
some of the things are ways of genuinely introducing new technology, new features etc
some of the things are just mistakes/screw ups/bugs etc
It's quite hard to tell the difference between the above four things as the effects on you (as a consumer) are often very similar and in reality it's often a combination of all four. I know this doesn't help if your xxx has stopped working, but, it's not
all profiteering, at least not all the time.
It's certainly possible to make plastic/electronic products that last for decades, if you design them (and the services they rely on) in that way from the outset. Unfortunately people often don't want to pay for products that are engineered in this way...