"MFC was introduced in 1992 with Microsoft's C/C++ 7.0 compiler for use with 16-bit versions of Windows as an extremely thin object-oriented C++ wrapper for the Windows API."
Thinness is probably in the eye of the beholder, but as one of the many MFC victims back in the day, I found using MFC to be endlessly frustrating because it added a layer of complexity and pain to Win32 programming without giving me anything I really wanted back in compensation - you still needed to work directly with arcane Win32 mechanisms to do simple things, like, change the background color of a window for example. Admittedly there was some (less thin) Document/View model stuff thrown in there, but the impression I got was that this was an afterthought bolted on the side.
In contrast, Qt and wxWidgets for example are toolkits that are designed to make a programmer's life easier by providing a genuinely convenient abstraction of a Windowed GUI.
I can't agree with this. MFC was a thin C++ encapsulation of the Windows API. It was a reasonably successful technology but was unloved largely because it was so thin - it didn't try to fix the ugly mess beneath and so left developers wrestling a large smelly octopus. .Net was more of a clean room attempt to provide developers with a clean, sane, consistent API built on a new virtual machine based architecture complete with a shiny new language (C#, basically Java++).