Farming engagement has no incentive.
I'm not so sure as I recall a power user on Reddit who consistently hit the front page as he figured out how to engage users (best times to post, which topics, phrasing, secondary accounts for initial boost). I forget his name, but he effectively was researching how to grab attention and then I think even went to marketing firms with his research on his viral methods.
At the time I recall people saying to me "it's just karma, it has no value" but attention was the value, and attention is something that companies can and will pay money for. Lemmy is not necesarily immune to this gamification of content