What would even be the point, how would you justify the expense of making modern CPUs 128bit (transistors and R&D ain’t free)? We aren’t anywhere near the limit of 64bit addressing and won’t reach that point for decades, modern “64-bit” consumer CPUs don’t even bother going for full 64-bit addressing space, since it wouldn’t be of use anyway. For arithmetic, it’s easily doable without any architectural changes.
What would even be the point, how would you justify the expense of making modern CPUs 128bit (transistors and R&D ain’t free)? We aren’t anywhere near the limit of 64bit addressing and won’t reach that point for decades, modern “64-bit” consumer CPUs don’t even bother going for full 64-bit addressing space, since it wouldn’t be of use anyway. For arithmetic, it’s easily doable without any architectural changes.