Having used Qt since version 4.7 and having started on a fresh commercial project involving updating an old Qt app to Qt 5, this is rather annoying news. To us (freelance) devs it means another cost item to justify, or we can bank on the LGPL and skirt the LTS stuff if the customer doesn't explicitly require it, I guess.
The requirement to have a user account feels like another 'user data slurping' thing to me. Where's the 'open source' spirit in that?
Maybe it's not so crazy to give WxWidget, GTK+, etc. another look. You know, just in case. Heavens know I moved all non-GUI-based stuff away from Qt to POCO.