Joe, the only world I can think of, in which every surface is moving at a constant speed relative to the surface beneath it, is a 2-dimension expanding Euclidean plane of uniformly separated points. Imagine a sheet of paper uniformly growing in size in every direction.
If you were a dot on this sheet, and could see in every direction around you -- on each axis of observation you choose, in every direction all the other dots would be moving away from you.
Now the kicker:
There is no mass in this world. What you call 'real' doesn't include you, the 3-dimensional observer. So suppose you want to say that the 3 dimension world is an illusion -- that we are all really 2-dimension creatures. Then you would have to explain the apparent existence of the directions up-down and left-right as well as forward-backward.
You should be able to deduce that the existence of six degrees of freedom on three axes instead of four degrees of freedom on two axes implies rotation in a spherical space. As a consequence, the curved motion you could not detect locally, on your 2-dimension plane, is evident in 3 dimensions as two components of relative motion: one component rigidly straight to your origin of measurement, and one around the curved space in your vicinity.
Here is what Galileo found:
In the field of your observation, the local gravity field in which you are at rest (not moving in relation to points of the field) other objects of 3-dimension mass that move toward your position accelerate at the same constant rate regardless of whether they move in a path straight to your plane (i.e.,in straight line free fall), or in a curved trajectory.
So whereas your 2-dimension world can only expand from the center of every point in one direction at uniform speed, the motion in our 3-dimension world is both uniform and accelerated. These two kinds of motion are described in Einstein's theory of special relativity (straight line uniform motion) and general relativity (accelerated motion).
So you're clearly wrong with your idea that all motion is only in 2 dimension (a surface and its sub surface). How about 4 dimensions, though?
When Einstein took the step of adopting 4-dimension Minkowski space for general relativity, the addition of a time component ("4th dimension") explained accelerated motion relative to uniform motion -- i.e., the rate of change in a system of coordinates is referred to your (the observer's) position in time as well as space, and physical reality is that of spacetime, not of either space or time independently.
So let's return to your world of uniformly expanding points on a 2 dimension surface:
That surface IS part of our real world! The most popular (and physically validated) solution to general relativity cosmology (the big bang) informs us that the universe is expanding at every point of spacetime. The origin of creation is literally both in you, and around you.
Abstractions regarding relative motion are actually more real than our naive perceptions of motion. Our physical space is 3 dimensional -- our brain-minds, however, are 4 dimensional.