I've suspected this for a while as well. I think many of the features we've seen released in tf2 has grown directly out of the development of DOTA2. Valve has practically admitted as much in the past by saying tf2 is a place where they experiment.
Let's consider:
* Replay system
* Training system
* Coaching System
* Microtransactions
* Trading interface
* Community Submissions + submission royalties
Who knows what else? At this point, I think tf2's success is going to influence DOTA2, and I wouldn't be surprised at all if DOTA2 is released free to play.
I probably won't ever play DOTA2, but I'm thankful for all the improvements to tf2 over the last few years. I'm just hoping for some mainly bug fix patches to be released soon as this point.
Let's consider:
* Replay system
* Training system
* Coaching System
* Microtransactions
* Trading interface
* Community Submissions + submission royalties
Who knows what else? At this point, I think tf2's success is going to influence DOTA2, and I wouldn't be surprised at all if DOTA2 is released free to play.
I probably won't ever play DOTA2, but I'm thankful for all the improvements to tf2 over the last few years. I'm just hoping for some mainly bug fix patches to be released soon as this point.