To be fair, FormState problems could get pretty bad. By default, large apps would be posting back several hundred KB on each click (sometimes even in the low MB range). With AJAX, it was better, but still not in the acceptable range for non-intranet apps. There were always mechanisms by which competent developers could work around these problems, but for the most part, those would mean that you're fighting with the framework and not working in a particularly idiomatic, WebForms-y way.
In retrospect, I'm not surprised MVC gained popularity so quickly.
WebForms was a beast and a horrible web technology for the web. I was just stating that, since MS intent on killing VB, it was intended to make transition from Enterprise VB Desktop apps to Enterprise Web Apps easier and in that regard it was successful.
The issues with FormState made it mostly unusable over the internet, it was relegated to intranet applications for the most part.
In retrospect, I'm not surprised MVC gained popularity so quickly.