I agree that the apps seem expensive. As a marketing strategy I would set the prices to be more attractive to members converting from Dolphin and New Installs. Should want to grow the install base and encourage site owners to expand features and buy more apps. Price is a deterrent when there are many opensource solutions such as elgg, humhub, ph7CMS and whatever the new incarnation of oxwall turns out to be (yes i now there are many others but those are the ones I have installed and played with).

I have posted about pricing before.  Though it is not a deterrent I am reluctant to spend heavily again as I did on Dolphin - "once bitten twice shy" as they say.