Intuit seems to be removing Quicken 2015 from the Mac App Store, or they leave it there for people to find it, purchase, and install it. Recently on firing up Q2015, I got a message that updates would no longer be provided through the App Store, and that I could migrate at no charge to a retail licensed version by downloading a utility. I did just that. It converted the installed application from MAS to one as if I had paid and downloaded it from Intuit, along with some much-needed bug fixes.
Guess what the next thing that popped up on my screen with my "retail licensed" copy of Quicken 2015... "Upgrade to Quicken 2016 Today!" ... back to the old yearly upgrade cycle for ... what... three features I don't need.
So, I took that as they need that yearly upgrade revenue, but it's not "frictionless" with the Mac App Store.
Seems to me these companies need to gravitate towards annual licensing if that is the only sustainable business model. Mac App Store needs to implement options to facilitate free trials, paid upgrades, periodic subscription fees, and a no-questions-asked automated refund process (like Google Play Store on Android). All that would go a long ways toward improving the App Store experience.
As a professional software developer, I have been tempted by handing over 30% of my revenue to Apple / Google to facilitate all that their app stores do. It would save me from hiring and/or contracting out to manage my own digital license fulfillment... heck 30% would be a screaming deal to have it all said and done.
On the flip side, 1Password from Agile Bits seems to be making the most of the MAS. You can buy it directly from them, of course, but if you buy it via the App Store, you can store your encrypted password vault on iCloud Drive, which allows more than just file-granular syncing, but record-by-record syncing. It's a huge deal, and one that requires Sandboxing, something only enabled when distribution is via the Mac App Store. Carrot/stick, perhaps, but it worked, and I bought my 1Password desktop app via MAS for that critical reason.
As to the junk in all the app stores, it seems to be a common problem. Even Amazon struggles with 99-cent Kindle ebooks that are just poor rips of public domain (and sometimes not!) literature. How do you police that? Opportunists will find a way... whack-a-mole, I guess.