Just hold forever and it's still good 1,000,000,000 years later.
Can we have such a thing?
Methinks such a thing would necessarily require it to be hyper-competitive. It has to stay on top of the game 99.99% of the time. It has to be able to become better than the best, including itself whenever it emerges. It has to be the unit of exchange for the world's biggest economy in the future. It has to be somewhat intelligent.
I wouldn't want to come back from my long offline holiday someday to find my portfolio rekted.
Unless, such a currency is somehow already the best and can never be bested forever, thus requiring no major changes. No amount of human and alien ingenuity will ever be able to surpass its perfection.
Is this Bitcoin?