There is an immense ocean of ideas out there. There are so much ideas (and combinations of ideas) that it is difficult/impossible to reach/analyze them all. People that choose to have a personal spirituality just take some of them for whatever personal reason.
We have a big diversity of ideas, but it's not just random ideas put together, it's a coherent system of ideas full of interconnectivity. We didn't create all our ideas, we have taken a lot of ideas from a broad and diverse range of sources (and sometimes with our own modifications). What it's new is our system of ideas. We still can include new ideas into our way of thinking (if they are good enough), or we can create new ones, we don't depend of the creativity of others.
