The industry has already done this in the past, so it's just a natural evolution of things.
16-bit PC's were operations until Windows 98 was released, which where the jump to 32-bit occurred (including the jump from FAT to FAT32 format)... this was back in 1998.
32-bit PC's have been in the mainstream until around 2009 with Windows 7. While 64-bit versions of Windows XP & Vista existed, most people didn't utilize it because of lack of viable software at the time (so 64-bit components were still hamstrung to the 32-bit limitations). These jumps occurred because programs & software were hitting the limitations of the bit range, mostly on storage & RAM.
* 16-bit -- 64 KB (65,536 bytes) max
* 32-bit -- 4 GB (= 4,096 MB = 4,194,304 KB = 4,294,967,296 bytes) max
* 64-bit -- 16 EB (= 16,384 PB = 16,777,216 TB = 17,179,869,184 GB = 18,446,744,073,709,551,616 bytes) max
These are running with the assumption of 1 unit = 1 byte. On storage, computers were increasing the "unit size" (also known as "cluster size") to temporarily side-step the situation with 32-bit storage limitations until 64-bit became more technically viable.
With the majority of hardware makers & OS going to 64-bit, software makers have finally made the jump & committing to 64-bit architecture & eventually discontinuing 32-bit. Even on the mobile side, Apple has discontinued 32-bit support (as Apple started making 64-bit iPhones with the iPhone SE & 6) & pulled all apps that refused to update to the 64-bit base from the iTunes store. Google is currently following suit with their transition to completely 64-bit with Android over the next year (they're still supporting 32-bit versions, but software makers MUST make a 64-bit version to stay listed in the Play Store).
The migration is happening right now, but it's more of a natural deal as 64-bit architecture is providing more resources than 32-bit allows as system requirements for games break the 4 GB RAM mark (the barrier between 32 & 64-bit), which many high-end games requiring at least 8 GB to run. However, only those who keep track of such technical things are knowing about this jump as the average user isn't paying attention to it (in line with the "Just works" mentality).
Hope this sheds some light on the subject.