The Brave Browser (https://brave.com/ https://brave.com/) is attempting something like this. (I expect compatible plugins for other browsers could be made in th

The Brave Browser (https://brave.com/ https://brave.com/) is attempting something like this. (I expect compatible plugins for other browsers could be made in the future if its system takes off.) There are complications that make this not super straight-forward to pull off. Low fees in cryptocurrency currently is usually done by having low activity. (There are several projects attempting to solve this in a decentralized way, including the Bitcoin Lightning Network and various Ethereum projects.) Then there's privacy issues.