[jnwatson]

You're already depending on the OS for many other things. Depending on it for page caching is just one more thing.

[bagxrvxpepzn]

This level of reasoning is insufficient when building reliable systems. The consequences of depending on the OS for page caching are different than the consequences of depending on it for device drivers, file systems, or scheduling.

[Creamsicle47]

Don't waste your energy. If you look at the guy's other responses, it will tell you exactly what kind of person you are dealing with.