Problem is when the shit goes down they ain't gonna be no drones bombing Iran, but the real deal. Of course they may send some in as Iran is tied up trying to deal with the real fighter jets. And to an extent, yes the U.S could be looking at a dire situation if it tries to occupy Iran, but if they merely want to bomb the hell outta their infrastructure and leave them in ruins there's not much Iran can do about it and most of the destruction to the infrastructure will be done and over with before Russia or China can find the keys to its war machine.

However, I agree if we go there to occupy then it could be as bad or worse than Vietnam. And doing so would allow the chinese n russians to show up in time to kick off ww3. Both scenarios would be very bad for all involved and diplmacy would be much better, but we know that ain't happening.