UTF-8 didn't win on technical merits, it won becausw it was mostly backwards compatible with all American software that previously used ASCII only.
When you leave the anglosphere you'll find that some languages still default to other encodings due to how large utf-8 ends up for them (Chinese and Japanese, to name two).
UTF-32 would be a fair comparison, but it is 4 bytes per character and I don't know what, if anything, uses it.
Then nVidia's moat begins to shrink because they need to offer their GPUs at a somewhat reduced price to try to keep their majority share.