The US, and likely Israel, want no US military on the ground. The risk of an international incident is too high with Israels indescriminate bombing.
Thats why the air drops and the pier exists. Even US soliders driving aid trucks, or maybe especially US soldiers driving aid trucks, would cause huge issues for both countries, even as it would likely save lives overall.
One “accidental” airstrike on a US military aid convoy and you have real shit happening. Not to mention Hamas, fucks that they are, would be glad to kill some Americans if they could.
Its a 70+ yr mess, and ain’t no one is solving it unless everyone involved is on board.