> there is no way they could muster the money and hardware to defend their patch of the ocean.

You also cannot defend a patch of ocean without some land, at least with current technology. War ships require quite a bit of time in dry dock for fueling, refit, and rearmament. And that's before we consider the subpar fighting capability that crews without shore leave would provide.

No, they'd still need to buy or borrow some land, even if they had the hardware to run a moderate navy.