at this point many are managed by agencies which can play that game on their own without even needing said influencers to knowingly and willingly collude

This is prominent in all engagement circles. A few months ago I somehow stumbled into a sex workers chat and it was filled with "Need boosts" and "I mod X, Y, Z subreddit and can get you verified and submission accepted faster". Engagement systems are awful imo, they've always been able to be gamed via click farms but most places can filter through inorganic engagement from mobile click farms in a single region, the "cheap" ones at least.