You're right of course the only barriers to immitation that any of us can think of are in switching costs. Interestingly(I spent A LOT of time in Internet 1.0 w/VC guys) investors get twitchy when you raise these as they're non-explicit; in that they cannot be made to appear for a product by injecting capital. First time someone comes up with a directly fundable anti-immitation protocol they should just invent a product to fit around it.