Neutralizing Malta does not end Britain's Mediterranean war

What if Germany and Italy rendered Malta as isolated and unusable as Truk or Rabaul became later in the Pacific War?

Britain loses Malta's immediate value but continues from Gibraltar and Alexandria until wider victories make the island operational again.

The counterfactual assumes Malta remains British but becomes unable to contribute effectively to the Mediterranean war. That would be a serious setback, though Gibraltar and Alexandria would remain available to the Royal Navy. British operations could continue from those bases. Success in North Africa or elsewhere could eventually make Malta operational again, while Valletta's resilience would make lasting neutralization difficult.