No upgrade??
 

I was on a flight on 2/7 from PIT to LGA. There were 2 first class seats that were empty for the flight. I noticed that the guy next to me in coach has Star Alliance Gold member on his boarding pass. I am very new to this upgrade thing, but why wouldn't he or someone else with status be upgraded to the empty first class seats?

They might have been Star Gold from another airline. They are not entitled to first class. Must have status with US for upgrade. However, a GA might upgrade another elite member from another program, but they do not have to provide the upgrade.

*G are definitely not entitled to free ug's. And most carriers would indeed prefer to have F seats go out empty than give them away. If people get too many of them without meeting the requirements, they will work less hard to meet the requirements and the carriers will lose the revenue.

I hate a lot of what the airlines do, but I agree with this one. It's like a restaurant throwing away the uneaten desserts at the end of the night. If you happen to be the last table to leave, does that mean they should give you a dessert for free?

However, I've only been flying a lot since December, but I don't remember an empty F seat on any of my flights.

I know the answer
 

After all US Preferreds (and companions) are upgraded, the GA may sell the FC seats (probably $50 for PIT-LGA) to anybody, though it's not unknown that an elite from a partner airline may be upgraded gratis last-minute by a kind GA.

The GA is under time pressure to resolve issues, get the paperwork done and move the flight out on time; sometimes standby upgrades may not be a front-burner priority.