Very pessimistic posts focusing only on commercial airlines.
I reckon BOH could survive limited or without airline services purely because of the large amount of other aviation services based out of the airport (& the business park). A nice length of runway, an abundance of space & good instruments, the facility is still prime aviation land - with the right amount of enticement if airline services were limited, I reckon many aviation services would jump at the chance to use the facility. Yes the current management are dire, but let's not give up hope - Hurn has plenty of life left in it, let's not condemn it to the grave quite yet.