Their Empire is reduced from what it was when Palpatine led it, yet they have the resources to build biiiigger superweapons.
I mean, okay, Palpatine tended to do it on the sly, so all of his superweapons had to be built behind cover, and use of resources that could be hidden from the Senate and such, so that could technically be why he couldn't just go big constantly. From the sound of it, Snoke doesn't have to worry so much about that, just keeping spies and rumours from kicking off about his secret superweapons and the like. But still, how does he have the resources and logistics for managing all of this?