That looks like snatching defeat from the jaws of victory -- a model that could have been a beneficial arrangement for everyone, turned into something overtly customer-hostile with a rip-off feel to it.
Doesn't seem that off to me. Perhaps you're just thinking about it from the wrong perspective.
Jetbrains has a price in mind for what they want to sell their software for, $X. You can buy it whenever you want for $X. To demonstrate that you may want to buy the next version of their software, they'll let you use the most recent version of their software for 12 months after your purchase, at which point they will stop and you will have to use the version you purchased.
Alternatively, as a different service, you can subscribe to the most up-to-date version of their software for a monthly fee. In an example of great customer service, Jetbrains will treat you at the end of each rolling 12 month period of subscription as though you had bought their product 12 months ago, and they will give you a free copy of that product!
If you're bothered that you can't subscribe to their latest-version service and then end your subscription and keep using the product, that's just silly. The price of the product is not $X/12, it's $X, and if you want it you can freely pay $X for it.
