Assuming that all marbles are equal in “attributes” (quantity, pattern, color, size and shape), the distribution of these would follow entropic distribution. Over time marbles would find their way to all “four corners” of the world.
Think about an enclosed cube. Spray perfume in a corner and the perfume molecules would ultimately distribute equally in the volume over time.
Marbles produced in Ohio would naturally find their way around the world over time.
A Christensen Agate Guinea from the 20’s has the same probability to migrate from Ohio to Montreal as it does to Rolla, MO.
Now, what changes the distribution is the “value” given to any one or multiple “attributes” involved. Equate money or beauty to gravity or magnetism. “Value” will usually find its way to the deepest purse.
Over time, a Guinea found in Canada would probably find its way back into the USA due to the attractiveness of the currency exchange.
Well financed collectors disrupt the natural distribution (entropy) of marbles. Their money acts like a black hole and soak up high valued marbles while leaving “lesser” marbles to circulate. (This is not a complaint. Just a reality. They take marbles off the free market and those remaining in circulation become scarce and increase in value. In time, those collectors have their acquisitions released back into public circulation due to disinterest, divestment or death).
Stay patient and enjoy the search!
YMMV. 😀