Even much more than that are ready to invest in ICO but the government don't make it easy for the american citizens to participate in ICO or even invest in any kind of crypto project that haven't been registered by the government, this is why a lot of companies that carry out ICO and create exchanges always restricts American citizens from participating, so that they won't face any kind of issues in the future.

I do not expect anything like that will be possible in near future. Because, this forum is purely decentralized in this regard hence we need to take ourselves secure by our own not by any authority hence no law will be possible to bind ICO operators. It means those number may change slowly as regulations is very unlikely to happen.