compute is not a moat, it's a rapidly depreciating physical asset. buying up all the shovels in a gold rush does not give you a moat, it gives you a slight advantage for the time being. someone else will just start making shovels. and the data is clearly available, hence the number of open-weight models.
Isn't a literal "moat" about temporary deterrence? I can imagine makeshift bridges could permanently make the moat useless.