I need a source? Can't you just believe me? 
Maybe I should rephrase my opinion as an opinion instead of a fact.
Why do I think this?
1. As far as I know, Intel and AMD have not produced 128-bit x86-compatible CPUs yet, and I don't think they would make sense.
2. 128-bit memory requirement also does not make sense (yet).
3. NTFS is currently 64-bit, but other file systems (like ZFS) are already 128-bit. The need for larger storage requirements is a lot closer than wider CPU or larger memory requirements.