Pottering about, as you do, I just found that Ballina had, wait for it, 509,579 RPT pax movements in 2017, after a steady upwards trajectory for the last 7 years. The Class D tower review criteria is... 350,000 (that number of pax was passed in 2012).
Where's the tower, Dick?
PS Arr, yes, the old Steamboat Springs, where the Firies run the Unicom. Let's have a look:
https://www.airnav.com/airport/KSBS
Not one RPT movement, let alone a jet, all bugsmashers, most based on the field. Great comparison for Ballina not.