It's qualitatively different, but there's some similarities in appearances. The end-user viewpoint, if this trend grows, is that the majority of the internet could present as a set of subscription packages -- the more you buy, the more of the internet you can access, and at higher service levels. Because of these new financial incentives, previously open, ad-supported websites will shift to becoming closed, subscription services: as the friction for end-users to subscribe to things goes down (because of federation*), this becomes more common. The open web goes dark. Conversely, since this is also an income source for the platforms/referrers, they'll want to boost referrals to partnering companies higher than non-partners -- tiered service. It's true this isn't the hard severity of an ISP throttling, or cutting off, non-partnering websites; but it's a soft analogue of it.

*(This friction can be zero. You needn't take any positive action to subscribe to the Nth website; rather the platforms you subscribe to abstract that away for you, as they monitor all your clicks and visits, and handle the income-splitting transparently behind the curtains. Basically the Spotify model, for the open WWW).