Actually, STS has been very busy this year. They lengthened the runway in 2016 (I think) to allow for 737s.

In 2017 STS added flights by: UA (SFO), AA (PHX), Allegiant (AZA & LAS), and seasonal service by Sun Country (MSP). I think Allegiant just pulled their service after AA joined in, though.

I believe there are even plans in the works to add jet bridges. I can tell you from personal experience that is a great idea. Pacific storms in March and deplaning onto a tarmac don't go well together...

There were a total of about 1700 flights out of STS last year and already 2300 so far this year. Pretty good growth!?