[dlgn]

The vast majority of Clash of Clans users pay little to nothing towards the game. They make the vast majority of their profits off a small group of users who they apparently refer to as "whales". It really isn't necessary to pay.

Furthermore, it isn't a single-player game, and the single player levels it has are a tiny part of the game that are demonstrably identical for everyone. In any case, the main purpose of Gem-spending isn't to win (you can't just spend gems and beat other players), but to speed things up. So, buying more builders, boosting barracks speed, et cetera. The only form of forced-frustration that really exists is when you have to upgrade something that takes a long time and is very important, particularly heroes and the spell factory (since there's only one of them). And you really can wait it out, you just have to have patience and change up your playstyle a bit.

TL;DR it really isn't comparable.

EDIT: not to mention that games, while they're still inevitably quantized at some level, have become much, much better at taking all of the player's actions and incorporating them into the world in important ways. See The Witcher 3, for example. And, after all, on some level, the real world is quantized as well. Granted, it's at a ridiculously smaller level, but still. It's a matter of degree.

[MindlessInsanity]

Of course they don't. Very little people are stupid enough to paying to play an easy game like CoC. Frustrated people who want to prove to themselves they can get a level done would pay money for a turn booster. (I see the same trick in Pokemon Shuffle) also I wasn't comparing those two games in that way. I'm just showing that most "free" games aren't free.