Coke stopped buying advertising once. Cause everyone already knows about them, so why pay for ads? Their sales dropped dramatically. Now they pay for lots of ads.
That's only surprising if you mistakenly imagine ads to be about competition. Instead, ads are about getting you to consume things you don't need, and since no one needs Coke,lless advertising -> less sales overall. Of course, that's only a bad thing for Coke, and should be encouraged actually.
https://hbr.org/2013/03/did-ebay-just-prove-that-paid
https://www.forbes.com/sites/augustinefou/2021/01/02/when-bi...