I of course can't talk for the full dev team so this is just my reasoning. But my answer is both it is technically difficult and not a priority.
First, contemporary Phones are designed to be limited. Touch screens are, for people who can use them (I can barely use touch screens so I am a bit biased), very good at a very limited set of input functions and very bad at everything else. Phone designers seem to have taken this and decided it is a good thing and run with it (I could probably write a very long post about just that, but that is off topic). Editing text is one of the things that they are bad at. I am used to using computers that I have customised a lot to work well for me, this makes using a phone to edit something like a wiki a very unattractive prospect. So I haven't bothered to try and make anything to work with a phone.
Second, phones seem like they are designed to be difficult to use for local productive work. Almost all of the development tools for android and iOS are designed around delivering content to a phone from a remote location and having the phone be a more or less passive recipient of the delivered content. They are easy to make things for where the phone is essentially a thin terminal for a remote server, but local content outside of the built-in media libraries is difficult to use. Some of this comes from the security model of phones which treats the person using the phone as an adversary (locked-down app stores aren't reasonable if you own the hardware. Sorry, some ranting is going to slip in). One way that this comes up is in access to the local file system and how aggressively sand-boxed applications are.
Third, developing for phones uses different languages and for the most part what you can use is pretty restricted. Unlike osx, windows and linux where I can write something in node (or python, or c) and then generate executables that will mostly work the same on all three operating systems without changes to the code, anything for iOS or android needs to be written only for iOS or android. There are some exceptions but in general that is true. If someone can find a way to compile an apk for android the way that I can compile for desktop operating systems that would let us make a version for android, but otherwise it would be a pretty large project and there are no guarantees that it would even work after the next update with how permissions on phones can change. For now the best option that I have, and the only one that has any reasonable expectation of working in a year or 5 years is to have a server that the phone connects to and use a browser like on a desktop. It isn't a good solution but I don't have any others.
Those are my thoughts and reasoning anyway. Others probably feel differently.