He’s the one to do the job.
(The Cambridge Grammar of the English Language, p.174)
CGEL says the meaning of the above “is comparable to that of the one who should do the job or the one whom we should get to do the job, with modal should”.
While I read that to-infinitives have the meaning of ‘potentiality’ (CGEL, p.1240~1243), I’ve not come across any mention about the modal meaning. Is the to-infinitive above has only the meaning of oughtness? Or could it have other meanings? (I think ‘He’s the one who would do the job,’ might be the candidate, but I’m not sure.)