I don't see the price raising people are talking about. See this page from 2008:
The Rio scenery 6 years ago cost the same 18 as now (now being the newer version). It seems to be their "release" price for big airports. I have been purchasing Tropicalsim, LatinVFR and other who creates airport in south america and caribbean and honestly I have not seen this raises on sceneries. It's the other things that are more expensive like gas, good, water, electric, etc... leavijng less for us to spend on hobbies. If add-ons for FS kept up with the inflation we would now be seeing major hub airports for over 40 bucks.