5W20 is the new 5W30 (and the old 5W30 ain't bad either)
If we were going to see anything towards reducing complexity in oil manufacturing, we'd see everything (except xW50+ oils) move to 0Wxx and everything else disappear
But with DIT engines and some of the technical papers coming out now, they are discovering the larger spread between the first and second numbers has generally resulted in higher wear, meaning 0W30 causes greater wear to things like timing chains and other sliding frictions than 5W30 and 5W30 causes greater wear than 10W30, where climate-applicable.
As was mentioned with SN+, ACEA ratings, upcoming GF-6, even conventional oils continue to get better and distance themselves much closer to synthetics than their brothers of 10+ years ago. As long as there are engines that were ever spec'd for 5W20, there will be those who buy 5W20 to put in it. Sure they could use 0W20, but the oil cap and owners manual say 5W20 for a reason, in their minds.