You know, we've considered it and we've been approached by a couple of publishers in the "hyper casual" space to go the route of free-but-with-IAPs. First the terms of industry-standard contracts are onerous. And second...well, I personally love casual games. And I never minded paying a reasonable amount for games I play. And then there are games like Two Dots that I really, really liked but the endless monetization just gets to be too much.
This is just our preference. We don't have anything against ad-supported or IAP-supported games. We just feel that there is still a pool of mobile players out there who don't mind purchasing a casual game outright.
And who knows, we might decide to collaborate with a publisher on a future game. We'll see what the future brings.