Me in 2090 BC, “Seems like people keep retelling this Gilgamesh tale and embellishing it each time! I’m really smart so it must people trying to convince me to buy something.”
Why would the Epic of Gilgamesh want to sell you something? In contrast this Sriracha story clearly does want to sell you something. If you want to use an analogy at least use one that makes sense.
Maybe that's a post facto rationalized reason, as I'm sure it did draw in more tributes, but that's like saying folk tales across the world's sole purpose is to have sacrifices when in reality people just like making up and telling stories. It's like saying the apostles of Christ only spread his message to raise money for the Catholic Church, no doubt that was a side effect but it wasn't the "point" by any means, especially early on where there was no church.
Because astroturfing on reddit exists doesn't mean that this is plausibly astroturfing. Any post on reddit about any business could be plausibly astroturfing by that logic.
Yes, the fact that I can even think so makes a case that it's possible to astroturf it. The same cannot be said of a folk tale, unless somehow it had its own interstitial ads between every chapter.