Vacuum Mystery ?

What are you calling "massive" and what are you calling "none?"

First, if you were to put a vacuum gauge onto the PVC valve (something which is mostly never done) you would read a high vacuum number at idle. THIS DOES NOT equate to a "massive" FLOW, because at idle, the piston in the valve is sucked up to restrict flow, thus NOT upsetting idle mixture.

THIS MEANS that at idle, there is LITTLE actual air FLOW VOLUME through the engine crankcase area cause by the PCV

Just about ANY blowby caused by even normal rings MAY nearly negate this, meaning, any vacuum at the breather is going to be not only slight pressure reading, but very little inflow, as well