> I am personally wondering if Yourube themselves are going to start implementing some thing like this sooner or later; after all, you are paying for an ad free experience on YouTube premium, just to watch all of those new videos become filled with in-video advertisements.

Unlikely. It requires monitoring content and ensuring they people add (correct) timestamps for sponsored content. This would need to be verified by YouTube moderators and in general requires a lot more resources than you think. Crowdsourcing like SponsorBlock is feasible but it's unlikely that YouTube will integrate SponsorBlock into the site.