I have seen that CPU's and operating systems have moved upwards in terms of bits from 8-bit to 16-bit, to 32-bit and currently to 64-bit. I understand that this change is to increase the maximum amount of memory that is addressable by the CPU.
What I don't understand is why there is always a doubling of the bus size. Is it just an arbitrary/business decision to double the bus size or is there another reason?
Why can't we have a 33-bit CPU? Or if that wasn't enough, a 34-bit CPU? 64-bit seems like such a massive and unnecessary (expensive?) jump in address space and presumably complexity of the underlying silicon.