This is part of why I'm completely ok with Jetbrains subscriptions - they have a perpetual fallback license. When they transitioned from the "buy a version, use it forever" licensing approach to a subscription model they added the perpetual fallback license (likely after some spicy feedback from customers).
You can use whatever version you've had for a year forever.
So if you cancel your subscription, the old version still works (and is probably fairly functional).
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The problem that Jetbrains had before the subscription model change is that major upgrade versions (that you paid for) were driven by accounting needs rather than engineering. "Need more money?" - release the version that is currently getting built, even if it doesn't offer compelling value. "Got some neat things for the next version?" - hold off on releasing it to customers until the company needs more money.
The subscription model made it so that accounting had a stable and predictable revenue stream and engineering could release things as features were developed.