It looks like they're encouraging (pressuring) open-source users to adopt the newer versions sooner. In this way, they'll get more value through those users as "beta-testers" through the feedback.
I can see many people are unhappy about this direction...
It's not only that - they are also reducing the contributions unpaid contributors will make (Qt was maintained to some degree by non-Qt-company people, only few will contribute to a commercial-only version)