It's not happening. Nothing is stopping other teams from using the tush push themselves. The Eagles are just the team that perfected it, which makes it sting, I admit.
Having said that, there is something of an unfair aspect when other offensive players can literally push Hurts or any QB forward for a first down. To me this is going to be a fad that goes away eventually. Once a QB gets his knee or leg twisted up into a season ending injury because of the tush push, it's going to fall out of favor faster than the wildcat formation.