But 32bit CPUs have 36 address bits so 64GB is the current end of the road, for now.
Theoretically, this can be extended further, but 2 years from now, a 32 bit CPU will be an ugly duckling.
Dealing with an ugly hack needed to use full 36 bit addressing on x86-32 is not for faint-hearted ... Certainly not for the mainstream consumer oriented software. Those who think 36 bit addressing is actually usable delude themselves.