I think in Europe they went to court to block these type of boxes. I am sure this is a precursor of what will happen in the US eventually.
https://www.ivacy.com/blog/eu-ban-kodi-boxes-are-there-alternatives/
In general the more popular and easier to access data that is copy writed, the more the copy write holders are going to pressure the government to plug the hole. The beauty of technology is that it is always one or ten steps ahead of the government for these cases.
Much like with torrenting, no one is going to waste the time going after the user, the government will try and attack the distribution model, which is where the can get the most bang for their buck. In streamings case, they are going to go after the Kodi plugin people if they can't make a case against Kodi themselves for providing the platform for people to access the copy writed data.