The Windows Shareware market died a long time ago... the market filled up with mostly free knock offs, and the quality dropped. There is some try-before-you-buy demoware, and some nagware, but no real "shareware" except a handful of IT Applications that old time IT guys are happy to buy.
Meanwhile, the Mac Shareware market has been doing alright. Versiontracker.com was THE source for Mac Shareware applications, but now it is as distributed and messy as the Windows one. The funny thing is, I have bought a couple of $20 - $40 utilities on my Mac, and small sized applications, and the process is annoying.
As a result, lots of shareware level software for the Mac has sold through Apple resellers and now the Apple store in boxed format. If you ever go to a Staples/Office Depot/Office Max, you'll see rows of that for the PC, the market still exists, we just ignore it because it doesn't cater to techies.
If I can setup a simple account with Apple - or use the one I use at home for ordering prints of the kids for great grandparents, etc., then I might buy a bunch of $1 - $10 utilities.
And that's great for the Mac ecosystem.
Will prices drop, probably.
When I see a program in an Apple Store for $50 (also available on their website for $50, probably contractual obligation), how much of that goes to the actual developer? $15-$20? (guessing retail + distribution channel grabs a lot).
If the developer puts it on the App Store for $30, he probably gets the same $20, and sells a lot more units because the price is lower.
This is going to be a HUGE boon for Apple developers.