When has it resisted molecular manipulation from a force as powerful as the power cosmic? He turns the tardis into cotton candy.
When has Galactus turned math into something else? Because the TARDIS is made from Block Transfer Computation, i.e. mathematical formulas that write it into reality.Also, turning the shell into something else does nothing to the inside, one is entirely mutable, and the other is in its own pocket universe.
And as I asked in my post, when has Galactus blinked away 11-D entities?
The TARDIS has never been destroyed, short of internal sabotage and almost by an Eign(spelling?) Ram (colliding with itself and annihilating itself). It survived having itself raped by a time line virus that turned it into reality cancer. It has survived materializing in a universe made of thought. It survived being turned into a thought in the Doctor's head. I am not saying that Galactus can't destroy the TARDIS shell, but it won't be as easy as turning it into cotton candy.