I don't think it's that massive. It's embarrassing and shameful, but the US navy has plenty of other bases that can take up the slack.
It was really stupid to start a war with Iran without first moving all the key personnel out of that base and redeploying them outside Iran's reach. The navy had to know that once a shooting war started, a base that was just across the narrow part of the Gulf from Iran, only 200 km away, was going to be extremely vulnerable. It is a sign of the kind of military that Hegseth runs that they had to abandon and evacuate that base once missiles started hitting it.
But, there's no need for the USN to be commanded from a building that's only 200 km from Iran. They can manage that fleet from the nearby base in Naples, or from a US base.
And, of course, if Trump hadn't alienated all the US's former friends and allies, there might be plenty of places between the Persian Gulf and Naples that would be willing to help with resupplies. But, as it stands, the US doesn't really have any friends anymore.