Qt started off with a commercial license in 1995, adding GPL in 2000. But the lack of an LGPL option is what (arguably) lead to the rise of GNOME/GTK when that project started in 1997, because it's the LGPL that allows organizations to write closed-source proprietary software without paying a license fee. [Edit: corrected Qt's original license history.]
Thanks for the correction. I'll update my comment. Either way, GNOME started out as LGPL, and it was the lack of the LPGL in Qt option (added much later in 2009) that I believe lead to GNOME/GTKs larger uptake early on.
The first decade was non-free with later various shades of semi-free. Around the turn of the century it was apparent Gnome was going to dominate the market unless they acted quickly, so they GPLed at that time to maintain relevance. They're still around; guess that strategy worked.
Having lived thru it, the situation was much worse than you imply. Its not that the non-free licenses didn't allow closed source or whatever, they more or less intentionally carefully prevented distros from legally including Qt. Just barely tight enough that on technicalities it failed the DFSG, intentionally. Debian couldn't include Qt and therefore KDE in main until the 2000 relicense.
