Notice in Pew Study Survey that in the US people attending church is at a all time low but belief in god is still the majority while Atheism is still on at 2 percent . This to me is a indication that US is slowly becoming more deistic. The only problem now is that people need to know more about deism as there few resource to go by. Deism need more publicity and strong advocates. Our own leader of deism if you like similar to William Criag is to Christianity or Christopher Hitchens is to Atheism.
Deism gained prominence in the 17th and 18th centuries during the Age of Enlightenment—especially in Britain, France, Germany, and the United States—among intellectuals raised as Christians who believed in one god, but found fault with organized religion and did not believe in supernatural events such as miracles, the inaccuracies of scriptures, or the Trinity. (Wikipedia) I believe Deism can compete with other mainstream religions, however you won't see people claim to be a Deist. I believe people will still consider themselves Christian even with these beliefs.
Deism can not compete with other mainstream religions. Deism is mostly a thing of the past and is not able to compete with most religions today. Most religions today have so much money and they are able to promote themselves. Modern day religions are very good at getting many followers.
Mainstream religions mostly expand because of missionaries. Deism is an important philosophy, but it will not be as popular as other religions unless it acquired a base of missionaries to find converts. There are simply too many voices out there in the religions community for Deism to make much of a difference.
I would say that at this point, the Abrahamic religions are too big for Deism to be a heavy competitor, but as more and more people start leaving the Catholic faith and other branches of Christian faith and religion altogether, I could see the movement picking up momentum. I think many people are just sick of the doctrines.
Although deism is an important philosophy, it will never be able to compete with other mainstream religions. Most major religions have missionaries who actively try to convert people to their beliefs. Deism has no such workers. Also, deism does not have an established clergy or support system, which most religions do have.