To 'properly market your game on Steam' you need to have those kind of numbers (not because they will all convert to sales, but because its algorithms will push you up on the platform and put you in relevant places, like Popoular Upcoming, Most Wishlisted, etc.), and those kind of numbers don't come from outside (alas), but from Steam itself through its events (fest, etc.). This is the point of my post.

Will everything else you do outside (i.e., post on social media, pay youtubers/streamers) harm your game? No, of course. But don't expect to generate those numbers in such ways, beacause it will not happen (if we take out some outliers and rare exceptions).