Yes, my first set of questions was overly speculative. But do you know how to explain what seems to me to be a contradiction between the claim that a Buddha is limited to a dasasahassi lokadhātu and the fact that nama loka has no space dimension along with the sutta I quoted that says a Buddha can make his voice heard as far as he wants?
Dhammacakkappavattanasutta:
Itiha tena khaṇena tena layena tena muhuttena yāva brahmalokā saddo abbhuggacchi. Ayañca dasasahassilokadhātu saṅkampi sampakampi sampavedhi, appamāṇo ca uḷāro obhāso loke pāturahosi atikkamma devānaṁ devānubhāvanti.
English: Thus at that moment, at that instant, at that second, the cry spread as far as the brahma world, and this ten thousandfold world system shook, quaked, and trembled, and an immeasurable glorious radiance appeared in the world surpassing the divine majesty of the devas.
Is the above sutta the source for the claim that a Buddha cannot travel beyond a 10K world-system (dasasahassi lokadhātu)?
Cūḷanikāsutta:
Ākaṅkhamāno, ānanda, tathāgato tisahassimahāsahassilokadhātuṁ sarena viññāpeyya, yāvatā pana ākaṅkheyyā”ti.
English: If he wished, Ānanda, a Realized One could make his voice heard throughout a galactic supercluster, or as far as he wants.