There's a difference between Clash of Clans and GTA V, though. There is nothing on any mobile platform that can compete in any way with any AAA game made in the last 10 years (the most advanced mobile game I see is GTA:SA, which came out in 2004 or KOTOR which came out in 2003). Hypothetically, if someone spends $60 on Candy Crush and $60 on a AAA console release, the Candy Crush developers are seeing a much more massive profit from that than EA or Activision see from their games. AAA budgets are well into the hundreds of millions of dollars. Candy Crush could be exactly replicated by a 14 year old in a high school Python class.
Only 2.3% of Candy Crush players pay any money. Meanwhile, King has 1400 employees and revenue of over $2.2 billion per year. But you know what's not fair? Take-Two, the parent company of Rockstar and makers of a whole hell of a lot more AAA games than just GTA, has a profit of $2.3b. I think the profit scales are tipped a little more towards the app developers than towards the AAA developers on this one, especially considering damn close to 100% of the players of GTA V paid for their game, and paid $60 for it.
Sure, not every developer is King and not all IAPs are shitty like that. But the minute I see "buy more gems for $1.99!", I delete the app. You might not get any downloads if you charge money for your software, but then again, as a mobile developer, you chose to enter that market. Which means you chose to be compared to all the other bullshit IAP scam games that dominate the "highest grossing" list. Don't want to be compared to the scam artists? Then don't play the same games as them.