Well, the good news is that IPv6 is winning. If Google's stats are accurate - and they probably are - IPv6 went from 1% usage to 16% usage in 5 years (January 2012 - January 2017). And in tech it's all about critical mass. We've passed innovators and early adopters and we're getting closer to early majority. I'd bet that once we're around 30-40% adoption will ramp up since few people want to be considered laggards.

And according to Google's graph I'd say we're about 5 years away from reaching 40%.