Amazon is funded by the sellers who advertise products through its Selling on Amazon platform, and eBay likewise.
Most video games with AAA production values are paywalled, either just to start (traditional distribution model) or to be able to play longer than five minutes in a stretch (free-to-play with energy mechanic). It's a consequence of needing to pay artists.
Ad-free sites hosting how-to articles would be paywalled. If you want to read five how-to articles, each on one of five different sites, prepare to pay five $20 per year subscriptions. If you think people don't read the featured article on today's Slashdot, just wait until site-scoped paywalls become more popular.
Likewise, ad-free messaging platforms would be paywalled. If one of your contacts is on of LOA, another on NSM, and yet another on QCI, prepare to pay three different annual subscriptions.