Given that companies often spend a significant fraction of their budgets on advertising, I wonder if some products would be cheaper if advertising was banned. Sure, maybe some ad-supported services would be paywalled, but it might end up being a wash in the end.

At the very very very least, every ad-supported service should be required to offer an option to pay and see no ads. I do pay for services I use regularly when they offer it as an option to avoid ads.

Companies spending money on advertising is just another way of acquiring customers. If they were unable to do that, they would need to resort to other, more costly ways of acquiring customers. I doubt that higher costs would result in lower prices for customers.