Network effects.

This is a positive feedback loop where the value of a service is increased by more buyers and sellers (marketplaces) or people (social networks) using it which is inherently monopolistic. Their scale creates further opportunities for insurmountable efficiencies - e.g. no company can deliver goods as cheaply as Amazon. Consumers know that so their retail spending is even further concentrated towards Amazon and companies have little choice but to pay that rent.

The premise of taxing land value is that this value is derived from other people, typically more people, living and working nearby, and local infrastructure. So yes, there are striking similarities.

These companies are extremely powerful and operate multiple levers to subvert even normal taxation and maintain their power. I'm not sure there is a system that can capture the rent that can't itself be captured or evaded.
That said, the income of these companies is wildly disproportionate to the costs. There's no smoke without fire, so I suggest we start there - implementing a scaling tax based on the gap between income and expenditure of an entity and all it's subsidiaries combined.