If someone is still using CS6 for their artwork because they don't want subscription and don't need certain new features and don't want to be locked out, that's fine.
So what's stopping them from still using C2 then? Nobody is forcing anyone to buy C3. C2 would be the equivalent of CS6. And C3 would be the equivalent of CC. C2 is still a viable option for people who don't want to pay subscriptions. Why do you have to use C3? If someone really need or want the features in c3 why not just pay up if they feel it's worth it, if not stick with c2.
I'm have both Adobe CC, and Autodesk Maya subscriptions as well, because I feel the upgrade is worth it. I could still use older versions but I don't want to, because I wouldn't get the new features. I prefer to have a subscription with regular updates, fixes, new features, and extended support. Something I will never get on the older versions.
If you don't continue pay subscription, you are locking yourself out. It's not Scirra. You can resub any time you want, or need to edit you projects. I don't see the big deal about this.
Would I lock myself out from my Maya and After Effects projects? Yes.... I do that all the time, when I know I'm not going to use it for a while. But when I do need it again, I just resub and I can continue where I left off, and I automatically get the latest versions.
Reading through the thread again I just get the feeling people don't understand upkeep and the costs of continued development by moving c3 online and adding online build service, or is just ignorant, or stingy. Like there's a lot of people who want C3 to be an all you can eat buffet just like like C2 with a one time pay. If you fall in this category, please consider to continue to use C2 instead, it's free for life and one time pay. The rest of us who believe in future Scirra products and want to support new features, upgrades, bug fixes can show our support by subscribing.
I already got about 3 years of free upgrades, support and bug fixes in C2 and I feel it's about time I chip in again. Even if I don't use C2/C3 daily or professionally I don't mind chipping in yearly, because I really enjoy using this software as my hobby, when I have time.