Journalists exist.
The best way to learn about new products is through influencers/reviewers/experts in their field. I'd even say its superior, which is why advertising companies ~sponsor~ bribe influencers to promote their products. Companies can also promote a product by sending it to reviewers.
So ads are not the only way to inform consumers, and the benefits IMO don't outweigh the cost.
In the same sentence, you give a possible solution and the reason why it wouldn't work.
Ban ads and companies are going to pay more and more for sponsored content to the point you can't differentiate what is legit from what is not.
Many “influencers” would have to go back to being amateurs. That’s ok. Some would accept backhanders, but they risk prosecution, which is actually possible [0].
[0] https://www.nzherald.co.nz/kahu/government-orders-maori-infl...
This would also include down propaganda on social media.
We could then work backwards to define exceptions such as politicians speaking in moderated debates, signage in shops, etc...
Defining this correctly will be difficult, but that's the case with any law. GDPR was watered down, and I'm still glad it's there.
The cash flow is: you -> merchant -> manufacturer -> advertising department -> google -> influencer
So if ads go away, theres two scenarios:
A: the influencer was worth your money and you pay him directly
B: he's not worth your money
I know, I'm making quite a few assumptions about how the market will correct, so I will also point that many Twitch-Streamer and YouTube channels already are financed through crowdfunding. It's not unrealistic that people will pay for good content.