It seems to me that the development of web app environment is very strong providing a richer set of capabilities and user experience than only a few years ago. I expect this will probably continue to develop. Ease of deployment is a factor as is the inherent cross platform abilities. Desktop app developers may need to reduce profitability to compete until a point will be reached where is makes sense to drop broadly marketed apps in favour of high priced niches, a scenario which would then accelerate. Mobile apps will only continue to flourish in a still expanding market, they have a marketing tool in the hand of every smart phone owner. The landscape will undoubtedly change, perhaps all surviving until the next wave.