Back then you'd have physical bulletin boards where you could either freely pin your handwritten note/"ad" onto or you'd have someone do it for you. Still technically an ad though.

It's the big players who have the most money for ads, buy up all billboards, internet and TV ads, etc. A small shop can't afford to do that. If ads were completely banned (in all forms including the bulletin boards) then everyone would have to rely on the word of mouth not just small businesses.

I also think that fields like photography are just highly competitive regardless of ads so it's then mostly a networking game.