Choice of game design and other human psychological factors aside

is the present hardware not capable of working with double precision floating point calculations with reasonable performance? It can ease all the complicated tricks involved to get large worlds working seamlessly in current single precision float setup.

Correct me if I'm wrong but shouldn't modern x64 processors more suited to this kind of task?

For the problem with gpu performance it should still be easier to work in double precision and translate co-ordinates to float on camera space