Determined Underachievers I think there are two aspects of ART which could help here.
One is the clear path - knowing that you are working through the levels, step by step, to one day ring a quarter peal or to be able to manage a touch in a minor method, etc. This can motivate people as it provides a next step to aim for but in this example you may need to emphasise that there is no rush, it’s fine to enjoy plain hunting for a while before deciding to try steps into method ringing.
The other is the celebration of achievements and sharing of satisfaction which comes in the Tower Talk newsletter and the ART Awards and that sort of thing. Knowing that many other people are also taking their next steps to improve their ringing and prepare to one day ring a quarter peal (or whatever) might also be a motivation that it really is possible, even if it doesn’t feel like it today.
The other big focus in ART is small steps, backwards to go forwards and break it down into smaller pieces. Maybe this learner will benefit from lots of plain hunting, getting really comfortable with it, before being ready to ask to try a next step.
It might be worth trying some methods which are a new challenge for everyone but still plain hunting for the treble, whether that is st Simon’s and st martins or double oxford or even stranger exercises like little penultimate where every other ringer is heavily watching / listening for the treble to know what to do themselves. Then everyone is getting some interesting ringing whilst this learner is ‘allowed’ to stay in the comfort zone of plain hunt (but likely acquiring improvement in rope sight and rhythm skills along the way).
I regularly ring with a Ring for the King learner who said early on that she only ever wanted to be able to cover well, then that she would only ever treble and is now ringing plain bob minor inside and trebling to surprise minor (and still fairly determined that she can’t try something new unless she’s had time to look at it at home first). She sets high standards for herself and hates to feel that she’s gone wrong and ‘ruined’ it for others. So, patiently, we are letting her drive the pace with an occasional suggestion of something she could look at next.
I found this article on the ART website (when looking for something else entirely!) and it shares why lapsed ringers said they enjoyed ringing and why they lapsed fro ringing and (in many cases) returned again later:
https://ringingteachers.org/application/files/3616/1220/8169/Why_do_ringers_lapse.pdf
The social side was seen as a greater motivation to ring than the mental exercise but the mental exercise is still a major reason to choose bellringing as an activity.