Originally Posted by Gate45

I think that’s wrong.
I have to do the whole “unnamed sources” thing, but the whole idea of PN and PZ is that it only is made available if that seat is otherwise expected to go empty. It’s not some generous favor to GSs or 1Ks. Instead it’s leveraging what is perishable inventory into a loyalty-generating tool - same for (saver) award inventory.
PN exists simply to give GS first dibs on that empty seat.
Now would they make more revenue if PN/PZ did not exist at all, yes of course because sometimes they get it wrong and release a seat that they in fact could have sold as demand shifts. But that’s the result of a (rare) revenue management error, not a display of generosity to loyal travelers.

​​​In other words: PP usage generally does not hurt UA’s bottom line and in fact is meant to improve it by preventing us from shopping around as we seek to increase our status/PP balance that we can then only use if UA says so.