Many types of Stand-by
The reason you end up on stand by has as much or more to do with success than your status.
For instance: Missconnect is NW fault, no matter what your status they should do everything possible to get you on the next flight out. That could equate to putting you first on the standby list. However, with a mis-connect that is NWA fault you should automatically be re-booked and not even have to fool with stand-by. Stand-by could come into play if the first "available" flight was several hours later, but there was an earlier one that you wish to stand-by on.
You show up late and miss a flight. Status could come into play here. But technically it is supposed to be first come first served, but I think in Reality they will accomodate an elite before a non-elite.
You show up for an earlier flight, Many times I have had the agent just directly book me into first class when I have wanted to leave earlier on the day that I already have a confirmed upgrade on a later flight. Of course there were seats available, and I am a Plat also. So I don't know if status helped, or the TA's being familiar with me helped more, but at my home airport they are always very accomodating.
Three different scenarios, all of them are "stand by" flights. Three different priorities. I guess ultimately it comes down to the agent working the flight or the agent at the ticket counter.