There are two ways it could work
All of the directors have been around the block a few times. They know that the Internet is largely funded by advertisers.
The threat of users moving en masse to Inrupt might be enough to bring the ad industry to heel. They might "voluntarily" agree to restrictions on how they collect and use data. Advertisers will have to be satisfied with extracting less value from data they collect. Advertisers will complain but live with it as long as nobody else can can do better.
Alternatively Inrupt could set up a micropayment system that replaces web-sites' income streams. That could make Inrupt the world's biggest bank. Advertisers will find other ways to reach your eyeballs.