Wow....we certainly are making this entire thing much more complicated than it needs to be.
As far as phone and tablet makers updating their OS versions that may "break" the Lionel or DCS apps, that is a totally normal thing in this world. You don't have to update your phone just because an update is available. Wait to update until you know the makers of the Apps you use have tested and announced the App is ready for a new OS.
As I know Roving Sign can attest to: Same really goes in our music world. Apple just released OSX High Sierra. Yet I, an many others who use our Macs in music production and performance haven't upgraded yet. Why? Because not all of the companies that make my music apps (VST/AU/Interfaces) have certified yet that they are done testing.
Apps and Operating systems are never going to remain in stasis. As bugs are discovered, new features added or needed, companies will update. If you get a notification that a new operating system is available for your device/computer, it is incumbent upon you to make sure your necessary apps will run on the updated OS.
I did the same thing when iOS 11 was released. I had to make sure my apps would be okay before updating my iPhone.
As far as DCS and Lionel Apps.... as long as the companies are supporting the app, there will be updates.
I know a lot of people are new to the OS/APP world, so my message here is in no way meant to be condescending or belittling. Just informative. The nature of Apps is that non thought of bugs sometimes are discovered after release. The developers work on it, then release version 1.1, then 1.2...major upgrade may then get Version 2.0..then 2.1.
If you are new to the App store/Google app store, Android store.... just scrolls thru all the things available and unless brand new, almost every app will be several updates down the road.
Finally, the companies and developers have to decide which platforms they want to release an App for. In this case, they decided Android and iOS were the most widely used, and most cost effective to put their developers on those.
If you have the knowledge to hack together something to make an app work on a non supported device, go for it. The fact it's not easy or fully functional is not a problem with the app.
Finally, as most of us have said, run your trains the way you want. Hand held remotes are still plentiful.
All I am saying is don't dismiss the paradigm of device/wifi usage out of hand based on conjecture and quasi-incorrect information.
I ran my trains from the handles last night. It was fun. I may fire up the wifi and use my iPad tonight...who knows? 
Most of all....have fun and go run your trains!
