Edit: As a sibling comment pointed out it does actually do paid upgrades after a year so ignore my comment.
The larger picture is, selling software somehow is always awkward. Given that, these folks have hit a near optimum, imo. And it's better to pay for a good tool than to find a good tool only to see the vendor go out of business. And that has happened plenty of times.
The adobe suite is bloated, slow, overly complex... There is a very strong niche for a suite or single tools that have better design, performance, integration and UX.
Jetbrains dev tools are highly praised just on their own and they have a strong plugin ecosystem (see: Cursive for Clojure).
Also these kind of developer tools have to indirectly compete with highly extensible and well established open source alternatives such as Vim, Emacs, VSCode who all have their unique strengths and support tons of languages.