G'day, if I might add a few thoughts on the debate?
Universal preasure, coming from all directions? wouldn't that balance out to zero? Take for example an object sealed in a chamber. The chamber would equalib equi eqk... balance out the forces leaving the contents of the chamber at virtual zero G, if I am understanding the idea.
The rubber sheet idea is far too simplistic to have any real value, but I wonder if 'we' threw out the baby with the bath water, when the idea of an ether was discarded? (No I don't believe in a flat Earth,... too many hills
)
Consider the effects of 'surface tension' on objects floating on a fluid, if there were a sort of etheral medium in which the physical universe was boyant then that would also give rise to universal attraction; provide a medium by rule of the density of which the limiting velocity is C, would be in harmony with relativity etc, etc.
The big problem I guess is that the physical universe doesn't lend itself to the idea of laying on a sheet; rubber or etheral.
cheers,
Doug