In an alternate universe, I wonder what would happen if we went the other way, allowing the walled groundskeepers their fences, but taking away all 'platform'-b

In an alternate universe, I wonder what would happen if we went the other way, allowing the walled groundskeepers their fences, but taking away all 'platform'-based legal protections that they enjoy; not just section 230: Apple liable for all copyright infringement, users defrauded by an app on the Play Store could claim damages from Google, etc. These protections are also precisely what the faux-libertarian defenders of Apple and Google's rights to shine their gnomes and trim their hedges ignore.