My question tag is similar to this one but I am asking a different question.
I am reading DN15 the mahanidana sutta where the Buddha says;
Suppose there were totally and utterly no rebirth for anyone anywhere. That is, there were no rebirth of sentient beings into their various realms—of gods, fairies, spirits, creatures, humans, quadrupeds, birds, or reptiles, each into their own realm. When there’s no rebirth at all, with the cessation of rebirth, would old age and death still be found?
"No, sir.” “That’s why this is the cause, source, origin, and condition of old age and death, namely rebirth. ‘Continued existence is a condition for rebirth’—that’s what I said. And this is a way to understand how this is so. Suppose there were totally and utterly no continued existence for anyone anywhere. That is, continued existence in the sensual realm, the realm of luminous form, or the formless realm. When there’s no continued existence at all, with the cessation of continued existence, would rebirth still be found?” “No, sir.”
Suppose in a hypothetical scenario in which all sentient beings which the Buddha mentions attain Nirvana and there is no rebirth here on planet Earth, wouldn't life as we know it vanish (Except for the trees)?
If there is no life, there is no Dhamma and no Buddhism. In that case wouldn't lifeforms emerge and evolve all over again on Earth or on some other habitable planet as they came to being in present form and all cycle of samsara and suffering and birth of Buddha all over again leading to absurdity of the whole endevour?
In that case wouldnt Buddhism be an effort to finish the sentient life and act against lifeforce as it is an effort to finish rebirth?