We certainly have the individual ability to build something like that. It's the togetherness and cooperation which I think is lacking.
Well, I do think that's the sort of thing that makes creative mode worthwhile, and there's been hints of things like that already happening in our survival servers - Frostfall, Retro's IC-lite, etc, that suggest to me that SOME people would be willing to be a cog in a larger scheme, rather than going off on their own tangents. I tend to despise creative servers filled with nothing but mega-coasters and big Megaman sprites.
What is important, for something like that, is a plan. A framework... At minimum, a rough sketch of what is to be built, a sample guide building(s) showing general architectural design as well as basics like how many blocks per floor, a list of permissible materials and other constraints. Put a foreman in charge of the different construction areas, and have at it.
There's several maps like that FyreUK one available for download so that interested people can see the level of organization needed. Tank has already stated that there's enough oomph in the server to handle multiple maps, including a creative one if need be (And it appears, with the Tamriel map, that we may be leaning toward this type of tightly controlled creative project). All that is left is to get interested people signed up and assigned roles.