The Qt Company recently changed their publishing model and they provide only recent versions as (L)GPL. Thus Open source users have to migrate to Qt 6 or run an outdated version of 5.7, missing bugfix releases. Migrating to Qt 6 however isn't easy as some components aren't available for Qt 6, yet. Thus Open Source users requiring those modules can't go anywhere.
Aside from that the Qt company restricted access to their builds behind a registration wall.
And if you are willing to pay they created a pricing model, which isn't easy to understand and can become quite expensive, (233$/month/developer) and as it's a subscription you can't simply pay a license and go from there, but you have to subscribe and the moment you terminate the agreement you are forbidden from distributing your application any further with Qt.
Thus unhappy open source users and many users who at least claim they would like to buy for sensible cost, but can't afford.
What about the approach that the Qt library uses, where they have a free GPL version and a paid commercial license? People might pay to avoid GPL obligations while using the library.