The physics community was already converging on the special theory of relativity when Einstein published it. All the signs were there --and had been for quite a while--, but someone needed to add 1 + 1 together and accept the implications. Einstein did that and his explication was very clear, making it immediately undeniable (which doesn't mean that it didn't take some time for people to acknowledge that). However, if he hadn't, one of dozens of others would have. The time was ripe and the evidence was clear.

  When Einstein published the General Theory only 2 other 
  people were able to understand it.

This is an urban legend. There were dozens of people that immediately understood it and hundreds that understood it after some additional explanation. That doesn't mean they accepted it in the absence of experimental confirmation.

However, the General theory was a far greater achievement than the Special theory, because the idea of mass influencing the geometry of space-time was far less obvious and it may have been a decade before anyone else would have investigated that possibility. Nevertheless: someone else would have come up with it. Einstein was no greater than any of the other great physicists of the time, who each had brilliant idea. Einstein just happened to have one that became widely known.