How? If you don't advertise, no one can see you.

How did people that had something to sell do it before advertising?

The problem again is greed. The organic way is too inefficient so advertising needs to come in and make people rich instead of letting the product do the convincing naturally, word of mouth and so on.

Advertising is as old as humanity itself. Asking what people did before advertising doesn't make sense.

Also, word-of-mouth advertising is, as the name suggests, a form of advertising.

If I need something, I’ll find it.

Just one counter example: gh.de

Not really a counter example: gh.de is a pure advertising platform.