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.
yes I agree with your first and third reasons because many of the current top altcoins will not reach their highest point again because the current creation of altcoins is very much and some of them will be in the top 10 - 20 positions on coinmarketcap. but I don't agree with reason no. 2 because on coinmarketcap it can be seen from the total volume that is there to occupy the top position. and there will definitely be the latest altcoins that are trending all the time, so the top altcoins will shift temporarily. so everything goes according to the trend.