The Qt company decided to screw their most important quasi-customer, despite a long and useful partnership: far less important paying customers should expect the Qt company to take advantage of them too.

For some the risk could justify switching from Qt to other libraries or to a GPL fork of Qt, right now, before it's too late.

Established companies rarely fall for the "We can't pay you but you get exposure". I don't think paying customers care about KDE or open source. If you can give concrete examples showing something else, it would be interesting.

The way to make money in open source is to sell service attached to software, software development as QT does it where services is small component is just not generating enough money. That's why RedHat is owned by IBM and Canonical Ltd. has revenue only 2x of Qt despite large number of users.

If Qt hadn't been taken up by KDE some other UI framework (such as wxWidgets) could've had much larger user base thereby rendering Qt much less attractive to developers and undermining their business model.

I personally prefer wxWigets over Qt, but I'm a user of both.

Does wxWidgets still feel like a 90's clone of MFC?

I developed MFC applications and wxWidgets is FAR better than MFC. Much easier to use too. Plus multi-platform.

Might be, I haven't look at it since late 90's.

So maybe it is worth another look.

However even OWL and VCL were better than MFC. :)

Qt is not being paid in exposure by KDE. Qt was in large part built by KDE, and if the KDE folks decide they want to fork it and get an organized response they might quite literally kill the Qt foundation by outcompeting them at every turn.

Trolltech was doing quite alright before KDE was even an idea and they have gotten more money from Blackberry, Nokia, Jolla and Ubuntu failed attempts than from KDE.

They are the only viable alternative to WPF/Win32 on medical devices, automotive infotainment systems, factory automation dashboards, MCUs displays, ticketing machines,...

I bet that whatever KDE decides to do it will hardly affect Qt's profits.

First they have to make KDevelop match QtCreator, 3D Studio and Design Studio, then we'll see.

Sure, but the threat right now is a fork of Qt that would encompass commercial features and be developed by the KDE community, the free software community as well as companies such as Bosch, Autodesk and so on.

That is a big threat to the bottom line of Trolltech.

While Blackberry, Nokia and so on contributed a lot of money, KDE contributed a lot of the product and to the technical system. That poses a unique threat of replacement.

Open source contributions back to upstream Qt, which includes KDE, have been between 10% and 40% throughout the years, and they have always been on core libraries.

To think that such tiny contributions would scale up to replace what Qt offers today, including supporting devices that require NDAs is utopian.