Literally, if there was some decentralized advertising network, that paid for web3, it would be literally no different than it is today except maybe the people making money in the middle would be taken out.
The main problem today seems to be that the average Internet user (look beyond the HN/techie bubble) prefers free services with ads to paying a fee. They know about the evils of Internet advertising in broad strokes, and they consider it a good deal.
Until this changes, all attempts to "replace" the Internet are dead on arrival. In the olden days of www, the number of users was so small that you could host your own site out of hobby and incur negligible costs. If you "replaced" the Internet, all the monthly active crowd from all the social media would flock to the "replacement" with similar demands (sharing photos, videos, livestreaming, etc.) and then again it's time to pay the piper.
Is that true? Do more average Internet users prefer free services where their data is being sold or where there is advertising? Any citations on this? On average, what percentage of users on leading sites pay a fee to remove advertising?
This is called "federation" and "peer to peer" and it already existed before "web2" and it mostly died because it was too much hassle for most people to bother with.
It seems with Helium, it's not some giant company in the middle monetizing both sides, but the fiat/HNT exchanges that are doing that.
Certainly, P2P services with federation require more people to put in effort, and for those that require each user to be their own node, unless they're designed to be very easy to set up, they're likely to fail to reach most regular people. This was part of the problem with the last wave of them, and could at least have been mitigated by better design on two fronts (first, designing the structure of the service such that it allows individual clients to connect to decentralized nodes run as servers, similar to Mastodon; second, designing the user setup process to make it easy to discover such nodes that fit with how you want to use the service).
But even with those drawbacks, some federated services were starting to gain some traction a decade or so ago. They died because the big players decided they wanted to own everything, and pushed their own services (see: all the various proprietary messaging services, etc).
Personally, I see decentralized, P2P, federated services as a necessary antidote to an Internet increasingly dominated by large corporations with a deep interest in harvesting your data. The problem is how to get there.
Sure, some sites have other models. But ideally you would like something as simple as putting a small ads banner on your website, without the inefficiency of wasting (website display) space, and integrity violations.
Edit: I'd be happy to transparently pay a small sum to each website I visit. If it was easy and and cheap.
An interesting feature of ads financing is that it is "progressive". The more money you have to spend, the more you are likely to spend on the advertised products. This effectively becomes a kind of price discrimination. But that's difficult to achieve with a "per view" price on a website.
Very few people have a problem with a small unobtrusive banner that's essentially an image and a link to some site. But filtering that away is trivially easy.
The ads we all hate, the 40-mb-of-JS-evasion-code monstrosities, the 'we actually compete against the CIA' data broker ads, the all-screen-flashing-ads, the 'watch this video first' abominations - those are comparatively hard to filter.