I've thought about this too, but I'm not sure I've got the patience to listen to articles read in TTS voice.
Anyway, on iOS if you enable voiceover you can read the entire screen by swiping down from the top with two fingers (I think - check the Apple website for accessibility information if not!)
You have to use the Speech from accessibility menu, and turn Speak Screen on.
Another possibility i just realised is the possibility to pass texts from reader mode into 3rd party text-to-speech application. Will have to research some of them.
Anyway, on iOS if you enable voiceover you can read the entire screen by swiping down from the top with two fingers (I think - check the Apple website for accessibility information if not!)