1. Many altcoins will never reach their all time high again.
2. Don't be fooled by altcoin ranks on coinmarketcap because many won't stay in top 20 anymore after we go deep into this bear market.
3. History have proven that many altcoins will be replaced by new ones and that's where huge investors will be making most of their gains in next bull market.
I don't believe in your statement that many of the top altcoins will be replaced with new altcoins, especially for eth, bnb and some of the other top rankings. but if there are many altcoins that become shitcoins after this bear market I'm sure for sure. I think there are some top altcoins that are really worth investing in. and if there is a new project or new coin it is not certain to be able to rank in the top 20.