Infinity is just a concept,,, and 100 years for us many will not even be alive so 100 or 1000 years makes no difference in the concept of infinity, which makes it perfectly valid for now to say Bitcoin has lifespan of infinity.
But so many things happen in tech in 10 or 20 years,,, we would have to adjust this thinking in another 10 years.
I think if this thread will be answered again maybe 5 or 10 years from now, then we will discover that the same answers will come out in the forum. And hopefully bitcointalk will still be here by that time. However, when we talk of the life span of bitcoin, i know it will still come to an end because even humans don't live until infinity. So same goes with the present investments today.
Bitcoin has been very good to us and definitely it really has a bright future. But the possibility of other investments to also come up rising in the market is very high so the moment bitcoin will no longer has its demand, then probably that would be the end of bitcoin.
If Bitcoin is around in 10 years, so will this forum. I cannot see a future where people are still using Bitcoin and no longer going to this forum. The OGs are here, the newbies after getting disappointed in other sites where there is only a desire for profit and not education, they will eventually find all the useful information here.
That 10 years is enough for me to say infinity. May it long be this way