So if I rasterise webfonts in a service I only have to pay once not per use? This sounds incorrect.
For either of the hypotheticals here, it would be possible to operate in the way described, subject to some constraints. There is no reason to think that the courts would perceive any legal imperative to recognize the distinction between server licenses or otherwise on copyright grounds. Companies can't invent law and say that it applies just because they wrote down how they'd like for things to work.
The technical reasons referenced earlier are what make these hypotheticals untenable, not law.