Airfares climb steeply for destinations in South

I find it amusing that the front-page headline and subsequent report in The Nation on Tuesday seems to suggest there is no wrongdoing on pricing of airfares.
I recently purchased flights from Samui to Suvarnabhumi and then on from the capital to Sukhothai (both return). The first leg from Samui cost approximately Bt10,500, whereas the second leg from Bangkok to Sukhothai cost approximately Bt3,500. Looking at a map of Thailand, it suggests there is not much difference in distance, and flight times are not much different either. And from Samui we usually fly on a smaller and thus presumably cheaper-to-operate plane.
I wonder what aviation bosses think of that?
Darren Blakeley