Back in the old days, people would share useful information in the internet of their own accord. That still happens a lot today, too! In my opinion, most of the stuff that's ad-supported is not worth my time, as the "content creator" is trying to sell something or otherwise has an angle they're pushing. How can I trust what they have to say when I know they're only doing it to make some money? They will be less interested in helping me than helping themselves!
I think if you take ads away from the internet, you'll also take away a lot of the bullshit and inaccurate or misleading information. If no-one is making any money off of it, you'll be left with largely relevant information.
The internet today is like a free to air television network, but I remember a time when it was nothing like that.