It's not In-App purchases, per se that are evil - I've spent around a hundred dollars on new levels (great use of In-App purchase - you reward the developer for creating new content), new tools, new capabilities in the last few years (much less than the the close to a thousand dollars in "up-front" app purchases I've made) - and I think I've gotten real value each time.
What's truly evil, is the cognitive manipulation that "free" games engage in on those who are most vulnerable to those manipulative techniques. The "Candy Crushes" of the world.
You want there to be a virtuous circle, in which developers are rewarded for creating new, and improved apps; not for buying extra boosters so you can clear the jelly without developing the skill required to (or wait long enough for an easier level). How stupid do you feel purchasing "Diesel" for your "Tractor" in a game? Particularly when you consume it and just have to buy more diesel to continue at any reasonable pace.
That's the evil part of In-App purchases - I can show you a dozen places where In-App purchases and/or subscriptions have been very well executed to the benefit of everyone. (LetterPress, Flickr, Whatsapp, Path, evernote, Pioneer Lands, Paper by Fifty-three - just to name a few)
It would be more helpful to show examples where IAP/subscriptions were well executed by your standard and still made it to / stayed in the top grossing list.
ghshephard gave a good answer to the question "why do many people consider in-app purchases evil".
However, there is no doubt that "evil" approaches are more profitable than the doing the right thing.
Techniques such as the ones described in http://www.gamasutra.com/blogs/RaminShokrizade/20130626/1949... are very effective, and developers who do use them are likely to make more money. But that doesn't mean that any means necessary to make it into the top 10 grossing apps list must be considered ethical.
What's truly evil, is the cognitive manipulation that "free" games engage in on those who are most vulnerable to those manipulative techniques. The "Candy Crushes" of the world.
You want there to be a virtuous circle, in which developers are rewarded for creating new, and improved apps; not for buying extra boosters so you can clear the jelly without developing the skill required to (or wait long enough for an easier level). How stupid do you feel purchasing "Diesel" for your "Tractor" in a game? Particularly when you consume it and just have to buy more diesel to continue at any reasonable pace.
That's the evil part of In-App purchases - I can show you a dozen places where In-App purchases and/or subscriptions have been very well executed to the benefit of everyone. (LetterPress, Flickr, Whatsapp, Path, evernote, Pioneer Lands, Paper by Fifty-three - just to name a few)