religion of one, it's also a lot easier to change. If I realize I'm suffering from arrogance, it's a little easier for me to address that than an organization of millions with all the inertia of 2,000 years.
I think for a lot of people too it comes down to whether they'd rather trust their own instincts and logic or trust (and this is purposely hyperbolic) a bunch of old, white, out-of-touch men that also seemed to condone sexual abuse of children. As I suggested earlier there's certainly a degree of arrogance in that thought (and we as a society have no shortage of arrogance), but I think a lot of people are comfortable saying they can have their own personal relationship with God without the need of some other group telling me what I should or should not believe.
My main point though is to question whether not being a part of organized religion necessarily makes one non-religious. I would posit that a person can still be religious without the organization.