Of course they know. I have seen local newspapers who managed to block archive.ph's mechanism. If a bigger outlet does not use technical measures against services like wallhop, it is safe to assume that’s deliberate.

It makes sense economically since the part of the population using such services is so small and may have specific demographics that justify specific treatment just from a marketing POV.

Then you want search engines to get the whole content (okay at least before they started to summarise everything but the kitchen sink) - that will always leave a loophole.