To the question of Getting compensation for it, they could offer a $5.00 version of it on the app store for Lion users. Thus, it's free if you upgrade, or it costs you a few bucks if you don't.
On the question of "upgrading hardware every year", every computer in my house is ML compatible, the oldest of which is almost five years old. So, it seems that as long as you've upgraded your hardware within the last few years, you'd be fine with this. This does make me curious about what the most recent machine that was Lion compatible but not ML compatible was...
In any event, is this annoying? Sure. Is it somethig to get all bent out of shape about? I don't really think so. I reserve getting all bent out of shape for things like discontinuing Rosetta support. $29 for an upgrade? Sure, until you factor in all the additional software that worked fine but suddenly won't run anymore because of the dropped Rosetta support. Lion cost me >$800 to upgrade...
It's not a question of not wanting to upgrade - I'd love to upgrade my 2008 MacBook to ML! All the sweet iCloud documents syncing with my iPad would be great!
The problem is that any Apple product with an Intel X3100 GPU or a GMA950 isn't supported by Mountain Lion. There are no 64-bit OSX GPU drivers for them (even though there are 64-bit Windows drivers for them, the rest of the system is capable of supporting a 64-bit OS, and Apple themselves even once shipped a buggy pre-release 64-bit driver in an OSX update before dropping it).
For some reason, Apple decided not to put the effort in to finish those 64-bit GPU drivers. Probably this same kind of planned obsolescence crap.
So yeah, I'd love to upgrade to Mountain Lion, but I can't. I did buy another machine (not for that - it's a RMBP and an enormous upgrade), but I'm not going to just chuck that computer away! It's going to my mum, who also has an iPhone and who I usually keep in contact with via iMessage.
Now I have to explain to her that, while she's messaged me on that same computer for months and months before now (and wanted that on her old windows machine), now she's finally getting a Mac but it can't do that stuff because Apple arbitrarily took it away.
Apple doesn't win anything by doing this to us. They just make it harder for us to communicate, and they give my mother a worse impression of Apple; as a company that actively takes away from its customers.
It also puts
all Apple's other iCloud services in to question. Can you really rely on them? How long before my Mac stops supporting PhotoStream, for example? Google and Facebook have rock-solid services that you can use from any damned computer, and they never go obsolete. You're better off using Google Talk and Picasa, or Facebook messages and photos, then relying on iCloud. Even if you're all in the Apple ecosystem.
They are novices at the service game. I hope they turn this around quickly. I've got to say, Apple under Tim Cook seems to be doing a lot more of this crap than they ever did under Steve. Sure, products always go out of date - but Apple never dropped their users when they could technically still be supported.
It's worse when it comes to services. Especially when it's a mode of communication like this. Doubly so when they've been using the product for nearly a year and there's clearly no technical hurdle to overcome; It impacts people in a big way.
