I'm guessing the sarcasm is because in truth that's only part of the answer instead of the whole answer? or does the sarcasm signify that it's none of the answer?

there's def many reasons why shitty social medias won out, and you certainly named one of them, sarcastically or not. others may include: dopamine driven content, marketing successes, corporate collaboration, random chance, that one media effect that has a name but is basically survivorship bias, and so on