Well, I thought the porn industry’s decision is what settled the argument between Blu-ray and HD-DVD.
I think that was between VHS and BetaMax.
While the porn industry effectively did decide VHS vs. Beta, they didn’t have much of a say in the HD format wars. They were actually migrating towards HD-DVD because of more relaxed terms and better support, but their content delivery in general was shifting to the Internet anyway.
This format war was decided by the big studios, aided by the PlayStation 3 putting hundreds of thousands of relatively cheap Blu-ray players into homes.