And this scenario where bakeries grind their margins in an endless ad fight is a bit far fetched, all the bakeries need to do is get your attention enough so that you know/remember they’re there. It’s a few cents with online advertising, FB makes billions because there’s a lot of users.

You’re also forgetting that such ads are about telling you about products you didn’t even consider you need. So yeah, you’re not going to die out of hunger due to lack of ads, but you may not learn of more luxurious items that you may want.

(Disclaimer, I work at FB, not on ads, and don’t know anything an outsider wouldn’t know)