The number of followers of Bitcoin is increasing day by day. There are Bitcoin investment enthusiasts all over the world. We can all see the daily transaction volume and amount. There may be new investment products in the future, but Bitcoin will not disappear. Bitcoin coexists with people.
Bitcoin will always remain like you said but I'm afraid at one point the cost of transactions and hence confirmations will be really high. Since we are talking about the life span and infinity, I cannot imagine why the miners would continue mining the Bitcoins if they aren't getting any block reward. Once all the coins are mined out and the block reward is almost zero, we technically need to spend enough BTC in the transactions for the miners to actually mine a block. I don't have the technical understanding of how things will work in the future when we reach such a stage but it terrifies me.