The problem of the "walled garden" also seems to be a solution to the "bot apocalypse" -- unless you put your site behind a paywall or a bot-proof login, it will be swarmed with automated traffic.

It's unfortunate that the defences, the "hardening" of sites leads to silos, but within these silos the very same forces (attention mining, etc) are leveraged for profit.

Beyond the wall the scavengers will eat you, within the walls you're put to work on a track.