I agree. The oil film left on the journals is enough to prevent metal to metal contact for the 1-2 seconds it takes for oil presure ot come up. Remember the oil pump is positive displacement and oil is non-compressible so oil will flow to the bottom end almost immediately, and to the top end a few seconds later.

I think the difference by adding a aftermarket pump would be going from an engine that lasts 200k miles to increasing it's life to 220k before a rebuild. If you look at it from a return on investment... it's probably cheaper to plan on having the engine rebuild 10% sooner. Put you money in a low risk Mutual Fund .... you'll make more money.

Also, an auxiliary pump is also one additonal item that can fail, leak and needs maintaining.