If anything this topic should have shown that there is a difference between testing well, and reality. More liquid (less viscous) pastes might test better, because they spread thinner, but they likely can pump out and dry out easier.
These so called real-life testing conditions, aren't really scientific, because nobody can replicate them, not all information is shared or known: like the distance between plates, or the volume and mass of paste used.
Also long term testing isn't something that most testers bother with, even though one could return to the same PC every year so after cleaning it to record temperature creep over time.
Absolute physical parameters that would provide a real point of comparison are never tested i.e. thermal conductivity, viscosity (both hot and cold) and others.