I think you are confusing principles with beliefs.
Principle is like a rule, standard, law or basic truth.
Belief is like an opinion or impression.
Your comments on the future generations' perception of love. - that
is just a belief.
A belief definitely does NOT become true simply because it's
fervently believed, or because it is believed by enough people. The
believer's certainty is not remotely a guide to whether or not the
belief is true.
Yes, the future generation will be different. Their beliefs and
practices might differ drastically from present day like you
mentioned.
But the one thing that don't change are proven
principles drawn from psychology, religion, philosophy, business,
economics, politics, history, metaphysics, etc.
Whether the majority choose to adopt them or not is based on their
own accord.
That is all to it when i said:
Practices change, principles don't.
Cheers