Correct me if I'm wrong, but there's no guarantee that the version you'd be downgraded to would be able to read project files from the current version, right? So if JetBrains decides to up the subscription price by a huge amount, you'd potentially still have to pay for a year at the new, extortionate price in order to be able to continue to build your existing code - and worse, they could remove the option to actually buy the version you're using altogether before you get the chance to do so.