I think you may be improperly conflating address or pointer width with the data types used for integer or floating-point arithmetic—we had floats up to 80 bits

I think you may be improperly conflating address or pointer width with the data types used for integer or floating-point arithmetic—we had floats up to 80 bits with "16-bit" x86 processors. Nobody's moving backwards in terms of pointer size. And any history of the progression of bit widths is incomplete without mentioning the SIMD trend that PCs have been on since the mid-90s, starting with 64-bit integer vectors and culminating in today's 512-bit vector instructions that re-use those original 64-bit vector registers as mask registers. I don't think there's any point at which PCs have ever abandoned 8-bit and 16-bit data types, or ever appeared to be on a trajectory to do so. We've just had some shifts over the years of what kinds of things we use narrower data types for.