In the original announcement for LGPL as a license option:
"Adding LGPL version 2.1 will greatly increase adoption of Qt across Windows, Linux, embedded Linux, Mac, S60, Windows CE, maemo, and Ovi web services. Having a larger number of users, including Nokia developers, providing feedback and contributions will help Qt remain a cutting edge, robust UI and application framework."
To me it seems like the intent was to increase adoption (including in embedded and mobile), but after the recent Digia/Qt Company corporate changes you can tell there's been a shift in the way the LGPL is interpreted. For example, before they had guidelines on their wiki (back when qt-project was still around) on LGPL compliance for mobile platforms that basically said 'Android was okay'... but now if you look at their new guidelines on qt.io after they changed everything, they are pushing for commercial license adoption. I'm pretty sure that was the motivation behind the LPGLv2 -> v3 change as well.