Mobile Radars still need about half an hour or more to be deployed, or to pack in order to mover to another place.
While US has 24 hours SATELLITE monitoring systems.
In open air, these mobile Radars are sitting ducks for US.
On the other hand, Iran has missile Silos which are considered safe while their dome is made up of Iranian CONCRETE, which is so strong that perhaps only the heaviest US bomb (mother of all bombs) could penetrate through it.
And I don't think Saudia has anything which could penetrate through such Iranian concrete.
So, would it not be wise to put Bavar type Radars under such Concrete Silos, where the dome of silos could be removed within 1 minute (in order that Radar could work) and then again cover the Radar within 1 minute against the incoming enemies missile?
LOL! If US Sat's had such capabilities the U.S. would have no need for Recon UAV's and Aircraft! And these are nothing but delusions in your head! And no one in their right mind deploys and operates a mobile Air Defense system from inside a Silo IT ABUSRD!
Hitting moving targets over areas that you don't have complete Air Superiority over is NOT easy!
And unless U.S. puts up SAT's with designated camera's for each Mobile SAM system in Iran then detecting and tracking each SAM system in Iran is NOT easy especially in a country that's larger than France, Germany, U.K. & Italy combined!!! And that's just the detecting and tracking part you'll have a whole other problem targeting and then hitting them with a weapon system from 100's of km away!
So no they are far from sitting ducks!
Silo's are much easier targets due to the accuracy of U.S. weapons systems and U.S. can equip it's tomahawks with 1000lb warheads capable of penetrating + 3ft fortified concrete bay doors and they posses the accuracy to hit those doors
Iran knows this and that's why they have built massive cavern type silos so they can take a massive explosion and quickly be prepped to launched another ballistic missile but SAM's are different and replacing the radars and targeting equipment of SAM's aren't so easy!
This is what an outdated Iranian SILO looks like and this was built during the time when not even the U.S. had the accuracy of targeting the launch bay doors with it's cruise missiles
Note just replacing the missiles inside such silos could take up to hours and repairing them if hit is not so easy and an explosion inside could render this silo inoperable for weeks
The picture below is of a more modern Iranian SILO
Note the missile gets fueled outside and the cavern has been built to withstand an explosion so even if they penetrate the lunch bay doors all they are destroying is a single missile not the actual silo and the reason they put such massive and wide doors is so that repair vehicles can come in conduct quick repairs and cleanup and tow in a new launcher & missile and have a new missile ready to launch from the same silo within hours
The U.S. doesn't have an unlimited number of Cruise Missiles and Aircraft deployed in the region so they have to be picky about what targets to choose against a country as big as Iran so the U.S. is not going to go after SAM TEL's unless a SAM Tel is equipped with it's own radar and targeting equipment like the 3rd of Khordod