Oh yeah, they indeed have fallen behind. Software even more than the hardware, iOS is just lacking innovation for years now. Android on the other hand has made some real astonishing progress, especially with Jelly Bean. iOS simply has become so boring.
I'm right now on the edge of replacing my 3GS and I never hesitated for one second that my next phone is gonna be powered by Android.
Considering you're using a 3GS, I don't think you're able to comment on the state of mobile iOS devices. You're using technology that is 4 years old. If you were complaining about your iPhone 5, then I would take your comment more seriously.