If you sat down everyone in the industry who had the same amount of education and professional experience, how many of them would have come up with a similar system? Sure there is more than one way to skin a cat, but after years of cat skinning school and years of professional cat skinning everybody comes to do it in close(maybe not identical) to the same way. I would step back and try to consider how unique the idea really is, and how easy it would be for someone with a similar background to figure it out just by looking at inputs and outputs.

Testing obviousness with the benefit of hindsight isn't always fair. :-)

One test for non-obviousness is if the problem has been known for a long time, but no one has solved it; or (even better), the standard approaches that are taught for it lead away from your solution.

Trading Technologies has in the past been aggressive about defending patents on their trading software.

On the other side of the aisle, many approaches are under trade secret protection.

I think operationally patents don't do what we would like, and that is to give a small innovator some room to profit from an invention. In real life, it is large companies that produce, acquire, and use them in a defensive fashion.