Bayaz. Spoilers here, beware

So, I re-read, or rather listened, 1st law and few of the single books and I can't for the mind of me, figure out why Bayaz has not been an eater for a long time now? Some people were throwing around theories about him being an eater in Heroes (nothing definitive from what I remember, it's the next "re-listen" of my books). Even if he was there, it's still... so late.

It just makes no sense, with his... well 0 morality when it comes to taking advantage of something. Even with Seed in his mind, he should've been an eater to start with, since he only needed Ferro to be the holder? So to actually get the seed, being an eater would've been a huge advantage?

If this has been answered before, pardon me, I have not gone through several page search in here. If it has been, all the better if someone can just link me to some answer. Being that it's been audiobooks and jogs for me, I might've missed some important information that reading books... uh keeps better in mind.