In a few years, many people thought altcoin would be destroyed, but the history proves that altcoin will continue to rise when the market is stable.
This is true. Many years ago people thought all altcoins would disappear and only Bitcoin would still exist. I was one saying no, alt-coins will always exist and Bitcoin will never be alone. It's normal for the market to try to find things of value, and with thousands of alt-coins there must be some value somewhere. This is healthy. Competition makes the top coins better as they can learn what the market wants.