I’m not sure what you mean by “entire stack” when it comes to mobile development, especially with iOS. If you want to target >85% of all devices, you aim for iOS current version - 1, then Swift and xCode your way into AppStore.
I am obviously over-simplifying it, but my point is it really depends on the market you’re aiming for. Like if you think you’ll make an app for users in North America, not supporting Android makes more sense. On the opposite side, if you want India, LATAM, you can drop iOS and never learn anything about Swift since your ROI will be very little. Again, heavily depends on what your goal is.
I am obviously over-simplifying it, but my point is it really depends on the market you’re aiming for. Like if you think you’ll make an app for users in North America, not supporting Android makes more sense. On the opposite side, if you want India, LATAM, you can drop iOS and never learn anything about Swift since your ROI will be very little. Again, heavily depends on what your goal is.