Here's food for thought:
Jesus was entirely counter-culture for his day. In an age and society where the religious elite would do as they please, Jesus cam and shook the fiber of everyone's thought. Deity aside, let's look at this as a two-fold possibility: we can look at the impact of his death, or assume what could have happened had he not been killed.
Things he *did* while alive was to stand in the way on behalf of women, such as the woman caught in adultery, where he turned away a death sentence simply by writing in the ground and making the statement "let he who is without sin cast the first stone"
He took up for the poor, like in the feeding of the 5000 (even if you don't believe in the miracle, you cannot deny it was his call to see to the needs of the people),
He helped the outcasts of society including lepers and those that were ostracized.
He sowed notions of peace and not revenge, fought for fairness and self-sacrifice in an age when it wasn't popular.
By the time of his death, he had people coming from all of Israel and further just to hope he would help or even to hear him speak. As he came into Jerusalem, the people were ready to crown him king, so much so that the leaders feared a revolt.
Keep in mind that he didn't lose most of them until after his death when they thought he would have an earthly kingdom. That said:
Even on his death, he brought peace to a thief being crucified. After his death, many carried his message to countless others across countless generations. Whether you call his sayings original or not, the ones who said it prior got little to no recognition. It was the life and death of Christ that gave those words life. It wasn't just 12 people that followed him after his death, but the impact of everyone that wanted him king in his life was changed. People that should have been dead, but gained life also passed his message along. Remember, by Acts 1 and 2, there was a group of about 120 men (not including women) that followed him and passed along his commands to form the largest following of today. Christ was a philosopher in action, laying down his life for what he believed.
Now, had he not been crucified, he may very well have sparked the biggest revolt in Roman history, and become the king of Israel going down in history with names like David and Solomon. Having even longer to impact more people instead of dying in his mid-thirties.