I’ve posted about my belief in the collective enlightenment before, but I wanted to ask Hindus/Buddhists about it specifically.
do you think there will be a time when everybody achieves Moksha/Nirvana?
I do.
Well I'm not a Hindu per se because my knowledge is limited to wikipedia articles and other posters on RF, but my beliefs are inspired by Advaita Vedanta (and Alan Watts).
I would say it's a confusing thing to think about. Everyone is one and the same, so even if an individual (illusion of ego) achieves Enlightenment in this life, there are still other lives out there to be experienced. I think Enlightenment is only for making this life simpler/easier/more enjoyable.
Not every individual ego achieves Enlightenment, you can look at any heroin addict shivering on the street begging for money, food, a blanket, or even just a hug and they die before they ever realize peace of mind.
But there will come a time when no life exists at all in the universe, and at that point in time there will be something akin to peace of mind.
(Just a disclaimer: I'm doubtful I'll ever fully reach Enlightenment in this life, that requires a lot of work that I'm not willing to fully commit to, just enough to bring myself back to happiness - attachment is real)