If no one individual or company can own land, then, by definition, the governing body that created the rule owns the land.
Since governments are in the business of governing, not real estate, they'll almost definitely outsource that work (or big parts of it) to private contractors like they do for defense.
The end result is that your landlord is now an even bigger private entity (that might be a conglomerate of smaller entities, which might or might not look like the institutional landlords that exist today) with the near-infinite financial backing of the government and the insanely slow processes that come with that (such as having to go through an intermediate to get that Tesla Powerwall you want to install approved, only to be told that Tesla isn't an approved supplier and that you should use this battery from $VENDOR_THAT_WE_DONT_HAVE_RELATIONSHIPS_WITH_WE_PROMISE).
Since governments are in the business of governing, not real estate, they'll almost definitely outsource that work (or big parts of it) to private contractors like they do for defense.
The end result is that your landlord is now an even bigger private entity (that might be a conglomerate of smaller entities, which might or might not look like the institutional landlords that exist today) with the near-infinite financial backing of the government and the insanely slow processes that come with that (such as having to go through an intermediate to get that Tesla Powerwall you want to install approved, only to be told that Tesla isn't an approved supplier and that you should use this battery from $VENDOR_THAT_WE_DONT_HAVE_RELATIONSHIPS_WITH_WE_PROMISE).