If it’s done well (and I’ve only seen a few such examples), it means that users who just want compatibility/security updates can get them for free and only pay for an upgrade when they want new features.
Which I consider the best of both worlds. But I’ve seen very few examples of this in real life, unfortunately.
Apps like PhotoShop are the outliers - most of the apps I used were reasonably priced and of very high quality. Even though they target a smaller audience than PhotoShop, there are no apps in the iPad app store like them.
I am thinking of things like the various compilers (Think C, Metrowerks, etc.), a very good data analysis and graphic program (Igor Pro), a free LaTeX typesetter which is relatively bug free and very well supported, and a number of others. Apple’s app store rules block any compilers or the multitude of apps available via Homebrew; the app store has nothing like Mathematica or Vellum (an excellent CAD program). Part of the problem for these apps is that they are very complicated, have a smaller audience, and need to be sold at considerably more than $10. The app store is not a congenial place for these apps even if they were allowed by Apple.
I think the issue here is they’re essentially ‘niche’ applications. I’m sure developers creating for smaller markets understand this and price accordingly. I have an app which is incredibly specific to my industry and it’s priced accordingly. A data analysis app is never going to sell quantities like a photo editor.
I don’t think Photoshop is an outlier. Back in the 90s there was a lot of software which cost a fortune. I recall our first version of Quark was $2500 (about $600 in today’s money). FMP was expensive and IIRC CodeWarrior was quite pricey.
For me non-upgrade pricing via the App store isn’t a problem given the prices are so low.
I don’t have apps in the App Store but if I was targeting the general market, there’s no way I could get the exposure I could get via the App Store. I guess it’s like a little cheese maker getting their product into Costco.
Yet, the Mac has many “niche” apps as well as “mainstream” apps (though compilers and other development apps are hardly niche). This is better in my opinion. We will just have to agree to disagree - the only platform which has apps I am interested in is the Mac. No point in belaboring this any more…
I don’t think we disagree, we’re just discussing the world as it currently stands 
Compilers etc are niche in regards the general user - I doubt many average users go to the App store and leave disappointed because they can’t find one. This is where Homebrew has found is niche, although even as an advanced user I rarely ever install from Homebrew or MacPorts.
There’s room in the world for website offerings and App store offerings. Whilst most Mac users will enjoy the convenience of the walled garden, it would be a sad day if it became the only way to get apps.
Agreed. Apple has said that they will keep the Mac as the only “open” platform they sell.