Yes, there are already some states in the US that have these tools. 

In terms of scalability I don't think there's any problems at all. These tools are blind to numbers, it's just a matter of adapting the signature triggers to the population of the US.

Regarding adoption, it's the same as every other political change, bottom-up and top-down. I'm a big proponent of bottom-up first, i.e implementing the 7 Swiss political tools listed above in a municipality somewhere, sharing the results with the world on the internet and scaling from there. That's the whole idea why I've created the website, Discords, etc, to get the movement going.

Are you interested in this kind of ideas? I honestly don't see any better alternatives to this. The alternative is just more polarization, conflict and wars, in the really dumb, brute force system that we have today.