I would think that being one of the top players in your industry for the last 20 years should count for something. I've done a couple of side ventures here and there that weren't directly tied to my field or scope of practice, but the connections I've made over the years were substantial enough that when people heard what I was doing they were happy to be a part of it, because they knew me and know what I'm capable of. When what I did for them was successful, they did most of the selling for me (both because they like me and because what I had done for them made them money).
Who are the people you know that would be happy to take a risk with you because they know you? It sounds like (from what I've read so far) that you're talking about a product for people who already have a successful business model. However likely your product is to generate additional revenue, changing a successful formula always carries with it some degree of risk and inconvenience, which most business owners are going to be sensitive to, especially if there's still a lot of growth potential out there for them that requires constant attention. I've certainly fielded my fair share of phone calls every week from people wanting to give me or sell me something that will "make me money".
"Everyone we speak to is enthusiastic but they have a full plate for their IT teams and don't really believe how easy it is to implement."
This really sounds like the crux of the matter. What could you do on your end that might address this for users (aside from simply trying to "convince" them that it's easy)? Maybe there's a creative opportunity here to find a way to address this for your customers so that they're more likely to onboard.