Specifically which layers would that be?
Specifically which layers are not compatible with CS what?
Kind of your fault for: buying into something new and hopefully useful and billable, then deciding it wasn't that cool so it goes away, then asking why you can't go back because you didn't handle your options with much wiggle room. It's OK to paint yourself into corners from time to time <g>.
IF you get this far in your story, you decide maybe, those features you thought were cool and paid for, are still cool and the alternative is to stop processing files, so you'll just pay the fee to Adobe and move on.
I think that's the right answer for you! Don't upgrade. Stick with CS6 which at some time in the future may die and you're forced to do..... All those years without the cool new features?
You're right, not subscribing to CC is definitely the right answer for me, but all in all I think it's still a valid point.
There were already a few examples of layer adjustments that won't register when you try to open the file in an older version of PS and I really can't believe that they will keep CS6 in sync with the future versions in CC feature-wise. Like I said, this isn't an issue yet, but as Adobe adds features in the future to the CC releases, they by all probability won't work correctly even with the last CS version (6). I'd like to think ahead for say 4 years here.
The issue is this: you subscribe to CC. They introduce new features with new code that work fine on the current CC version. So let us say you use those new features on a file and they create new adjustment layers, or you use new layers for them. You decide at the end of your contract to de-subscribe. You have your files alright, but you are only left with legacy CS6 to open them. If CS6 doesn't have the code that enabled the new features you used on that file while you were subscribed, those edits likely won't be accessible in CS6 which is all you are left with (if you had it to begin with - people starting fresh won't even have that). So if you think at some point you may jump off the train, you need to at least create a version of the file that merges all the layers created with new CC code into the background layer. By doing so you lose the non-destructive reversible workflow approach with respect to those things you did in CC that may not be recognizable in CS6. You can avoid this inconvenience only by either staying aboard the train or merging nonCS6-compliant edits into the background if you ever think you will jump off the train. So people feel "chained".
Mark put it so clearly here, that I'm quoting him rather than trying to re-write what he wrote.
For painting oneself to a corner, are there much options? Adobe wiped out those options with one swift move by forcing the CC subscription system.
And sometimes things are not that black & white as where "one just decides that it wasn't cool". First of all, not all Adobe users are pros who sell their work or sell their work only occasionally. I'm in the latter group and really don't make much money with photography, so yes, I'd like the chance to skip over versions and decide for myself when to update (and when I have sufficient funds to do so). So maybe I don't think that something is "billable", but I'd like to keep with the times still. As a non-pro photographer the software doesn't have a ROI for me, it's pretty much just an expense, plain and simple (well ROI = continuing my hobby and selling the occasional print). This brings me to the point of increased cost of the subscription model compared to the old upgrade path if I only need PS. Don't get me wrong, the cost is still doable with a steady income even for the hobbyist. But like I said, life isn't always that B&W, for example I'm unemployed at the moment, so cutting down costs is a necessity and I think the CC subscription would be the first to go. Also I don't believe for one second that the price will remain the same as years go by, so this alone could go over the pain threshold (this is speculation based on the way things are developing in the world).
So you're forced to fall back on what ever version it was before CC or worse yet, you were a new customer, so you have absolutely nothing. This would get even worse if LR would go to subscription model only, but hopefully you'll catch my point here. The files themselves are not going anywhere and you can still work on them with whatever you choose, but all the time maintaining your catalog, key wording, developing and doing edits in PS would be locked until you can once again afford the subscription.
I know the new model is really great for some people. Especially for those who use multiple applications in the suite and of course for pros who can easily cover the expense on a monthly and yearly basis and deduct the costs from taxes (don't know if that's the right way to say it, but again, hopefully the message comes through).
I'd say the bottom line at least for me is that I really don't like the idea of Adobe billing my account for a certain amount of money every month till the "end of days", which will pretty soon amount to a sizable sum and if for some reason I can't make that payment anymore, they "hold the hours and hours of work I've put in" for ransom. Mind you, not the files themselves, but the work I've put into them.
Disclaimer: there might be something incomprehensible in the text above since I should've been in bed several hours ago. So I'll apologize beforehand