I doubt you're right that Apple's more-strongly leveraging dark patterns (... do they?) is the reason iOS users use their devices more, and spend more money on them. There probably are several things that all contribute, but I doubt that particular one ranks in the top-10, assuming the effect even goes that direction at all, and I'd certainly not bet that it does.

I mean, hell, Apple goes out of their way to let you know how much you're using the device and where you're spending (or wasting) your time. And they make managing e.g. subscriptions dead easy. Sure seems counterproductive if the secret of their success is dark patterns tricking us into spending more time on the devices, and spending more money.