Bitcoin can't be replaced by any crypto coin, Bitcoin is what has been given other coin Hope and is like the head of cryptocurrency without Bitcoin there will be no cryptocurrency development, Bitcoin is the only coin that is accepted in many countries and with the long term growth and impact it has made for years now.
Bitcoin is a decentralized coin and can't be affected by any government policy or war, I don't think any coin will grow more than Bitcoin they will always be under Bitcoin.
Bitcoin will always remain the best in the world.
When you talk about being replaced by other investment, sure other better investment will come which could be better than Bitcoin investment, who will ever imagine 20 years back from now that an investment like Bitcoin will come in place and become one of the best investment in the world right now, as time goes on other investment will come which may be more better.
However the only investment that can replace Bitcoin is an investment that can accommodate the poor and can be done anywhere in the world without any government policy accepting it.
But one should not wait for any investment coming in the future is better you engage in Bitcoin now since it's a good investment and since it has not reached half of it's growth.