What are the factors influencing the US Navy's position here? Not enough small/cheap ships for this work? Too hard to defend against guerilla speedboat attacks?

It seems like Iran has a lot of options for attacking ships. So far theyve used speedboats to attack tankers in Iraqi waters and they used "unknown projectiles" to attack ships in the strait. The ships are on fire and crew have died with the remaining rescued by Oman's and Iraq's navies. I don't know what a us navy ship is going to do as an escort other than be a sponge for incoming projectiles.