Having listened to the relevant section of Ven. Bodhi’s talk and done a cursory search through the suttas, I take this back. There are various instances of both dhātu and āyatana that do not support Bodhi’s notions that it is an ontologically positive, a certain existential state. Quite the opposite.
I won’t list all I found. Ven. Brahmali already mentioned nirodhadhātu, the “cessation-property”. In a sutta specifically called Dhātu-sutta in the Itivuttaka (Iti51), this is clearly a synonym for nibbāna, called there also the deathless (or ‘death-free’) “property” (amata dhātu).
MN102 (Pañcattaya Sutta) lists five categories of wrong views which among which is annihilationism. These are called āyatanas. I would translate it maybe as ‘options’; Sujato has ‘theses’.
Of course both cessation and annihilationism are the very opposite of an existential/ontological reality.
Perhaps I just trusted Bhikkhu Bodhi too much by assuming it would be hard to refute.
Ven. Bodhi also mentioned dhamma, but I’m not even going to search that word. It’s probably the most fluent word in the Pāli and vayadhamma, ‘nature to vanish’, is very common.
I touched upon padaṃ a while ago.
@Javier, not wanting to start a new argument. 