The thing is, this free-to-start model is, in my opinion, not the best option at all. Or at least make it less expensive. Look at Pokémon GO, the game is freemium and at its peak it made USD$10 million a day. In less than three months it hit the USD$600 million mark.
Let's take Super Mario 3D World, the latest installment in the Mario series and the fourth-best selling game for the Wii U. In over three years, it has made around USD$300 million. Half of what Pokémon GO made in only a twelfth of the time.
When it comes to mobile, you want volume. You want a *bleep*ton of people downloading your game for free and a fraction of them paying for extra content. You want it to be a massive phenomenon, even if just for a few months. You don't want a very small fraction of mobile phone users buying an expensive game. Just look at the top grossing apps chart on your app store; I'm looking at the Mexican Play Store and the first paid app (Minecraft) appears in the 28th place. The it's GTA in #49. Then that's it, if we go all the way down to #100. Only two paid apps could "rival" free apps in revenue; and let's be clear, they have no chance at matching them in downloads. Oh, and those two apps are around half the price of Super Mario Run.