Media advertising exists at least since 18th century (in our common modern understanding, commercial and political writings that can be reasonably considered ads were found on the walls of Pompeii, and probably exist since writing was invented). So there pretty much was never a period where modern capitalism existed and advertising didn't.
> How would overt modern advertising have fixed that?
It is not fixing that, it is a direct and inevitable result of abundance of resources. If you have surplus of resources available for consumption, you will need to choose which ones to consume. Thus, advertising - i.e. speech that is intended to make you to choose one particular resource - becomes profitable.
> Does advertising even help with finding decent food
Depends on advertising. Some does, some doesn't.
>I've lived in another kind of society - where people spend resources on finding way to get decent food, clothes, books, etc.
How would overt modern advertising have fixed that? Do you think we don't spend resources on having the advertising find us instead of us finding the products? Does advertising even help with finding decent food, are lies forbidden when you advertise?
There's a wide gulf between advertising you have the cheapest apples in town on a sign in front of your store and advertising Red Lobster's Lobsterfest. Capitalism works fine under either example though.