Because it's well established that game developers can and will jump through whatever hoops the platform holder demands at their own expense, they don't have the leverage to be picky about the technical details when deciding which platforms to ship on. Nintendo doesn't need to create new incentives to release on the Switch when they already have the biggest incentive of all: 140+ million units sold, and a high attach rate.

At least there isn't as much hoop jumping as there used to be, since the systems have all converged on using commodity CPU and GPU architectures with at most minor embellishments.