It may not alter their pay immediately but if enough people start using SponsorBlock, it seems like a logical conclusion that the sponsors will see their ROIs drop and will start paying less for sponsored content.
Only if you were actually going to be influenced to buy the thing in the first place. And it's not like the various bits of advertising from a sponsorship go entirely unnoticed in many circumstances, with various requirements to add text ads to video descriptions and pinned comments.
If you're looking to be actually informed - rather than manipulated - you're not missing out on much with SponsorBlock.
Not to mention I've never actually seen anything both potentially useful and novel-to-me show up in a YouTube sponsorship anyway. It mostly seems to be full of companies with established models looking for ways to boost their adspend even higher after they've tapped out other avenues.
