Yes, it has, but not to a degree that the sleeping giants have decided it's time to wake up and act. The thing the US hopes for is that the Houtis will see reason, if they don't they can expect to be wiped out. Give it some time, these operations aren't planned on the spur of the moment. You can bet your ass that right now somewhere in the pentagon a set of rooms is dedicated to dealing with this. And until it happens it will seem as though nothing is going to happen.