If you haven't played Game of War you should. It represents a genre which kickstarted f2p in Europe. Among the originators was OGame, Tribal Wars, Travian, Ikariam, Grepolis and more. They all follow the same principles invented by a game called Planetarion - which failed to monetize as f2p wasn't invented back then.
And believe me every single game I mentioned is better than Game of War. So why do people play it and why is it so successful?
Game of War violates pretty much any f2p fair play rules. When you log back in after some days absence you have to close sales pop ups like crazy. Generally this game tries to sell you something at every corner of the UI. And it gets on your nerves, it disturbs game play. It is bad.
But it makes tons of money.
Why? Several reasons.
It was a first mover. Game of War was one of the first games of that successful genre being on mobile in a pretty solid quality.
It is a whale hunting game. The conversion of the game is bad but the ones who pay do so in exorbitant value. From stats I know it is by far the game with the highest average spending per paying user (ARPPU). Note: the value shown in the link is average YEARLY spending. Note 2: Some games excluded like Puzzle & Dragons which features a higher but only in Japan. Lets stick to world wide.
It is attractive to new gamers who don't know better. Yes. This. This is the prime reason. You should know that most gamers on mobile are new to games. This is a fact. So when they play Gamer of War they simply do not know the better ones. The the competition is either copying the bad style of Age of War or isn't known to them due to less marketing spend.
And the operator of Game of War knows this and puts their marketing where the new gamers are: on TV. TV ads attract a lot of users who aren't experience much in games. And when they are attracted ti strategy games they might try Game of War. The bad things of the game like the push to sales and pop ups are just something they think is normal. They accept this. Experienced gamers wouldn't. But those are the minority compared to the vast size of the mobile market.
There you have it. Game of War is successful as most of their players are new to games but fascinated by this successful genre. Competition is fierce. There are literally hundreds of these games in the App stores. And many of them are better. Some company make their living out of them like Kabam or Plarium.
The sad side story? German f2p publishers established f2p in Europe with this genre pre 2010 but lost the lead 60% market share (!) as they were too slow to move to mobile. Very sad.