There are accepted world-wide practises that cater for such developments,
Is there? ICAO's got nothing between a "nothing" airport and a Class D or higher tower. We've got "nothing", then mandatory radio, then CAGRO/AFIS, then tower. Seems more logical (and cost-effective) to me. And we don't need a tower at Busselton or Kal!
The reality is both these balls-ups have been caused by communications. Using CTAF and ATC together (Mangalore) or Ballina where the Jab, A320 and the missing-in-action CAGRO could have done better.
An airport can voluntarily develop runways, taxiways,
You're dreaming, Geoff. If it won't make money, they won't do it unless they are required to. 400,000 pax, multi RPT flights a day, and still only 30m wide, only 1900m long and no parallel taxiway. Seriously??
I agree with your point regarding a "private" tower. Probably have plenty of takers for ATC in that part of the world. Apart from the rent.
Oh, I forgot, ATSB thinks ADS-B will solve the problem, clearly they are not the solution, just part of the problem.
Really? Cheap ADSB Out on Jab, ADSB In on A320. And SFIS can now see the Jab. Provided it's switched on, of course...