That's a misconception for a couple of reasons. Firstly, the pilgrims that came here looking for "religious freedom" (they actually just didn't like the way religion was handled in England at the time. nobody forced them out they were just kinda like "eh this isn't working") aren't the founders. Most of the country was farming operations that were run by people who were already rich and offered the very poor a "new life" in exchange for labor. New England is where the religious shit went down, but everything south of that was tobacco production (maybe some cotton? it's been a while).
The founding fathers as we know them weren't really poor. We like to say that they were all self-made men but they didn't start from scratch so much as they had a lot of work ethic, which starting from scratch will actually diminish fairly efficiently. But there's a reason Ben Franklin is on our $100 bill. They also weren't very religious. Deism was the popular philosophy among intellectuals of the time period. Jefferson is famous for having cut up a Holy Bible and only keeping the parts he thought were relevant.
Edit: <Insert insensitive statement about how moving upward in a class structure is and always has been a myth>
