Yes, that’s true for the price of the application, but I think that it’s important to specify that the app price is not the main way game apps earn money on mobile devices. Freemium + in-app purchases is.
Now, I understand that the in-app purchase model would be difficult to apply to PnC adventure games, but just to explore a bit more what this kind of games can achieve, let’s have a look at actual data.
Today, June 4th 2017, Clash of Clans made 2,019,896 USD in revenues, in US only and on iPhone only. I’ll write it again: Today. April 2017 daily average was 1,975,223 USD.
If you read the list of the most-grossing iPhone game apps, you’ll notice that the freemium + in-app purchase is pretty much the only model that lets the developers to get a good and recurrent income.
Of the top 194 top-grossing games, 192 are free, that is, you do not pay to play, you pay only if you want or need to add/do more stuff to the gameplay.
So, it’s true that if you exclude in-app purchases the price of the app is the only source of income and that you have to fight the free-to-play mobile user culture, but maybe, just maybe, it is possible to create a PnC adventure game with in-app purchases and embrace the freemium model instead of fighting it. 
You don’t even need to transform your users in addicted zombies like most games do: the quantity of things to purchase within a PnC adventure game could be limited.
I would have liked more specks of dusts to be spread around, for example.
Just food for thought…