Then you heard the wrong thing, a typical example of a major altcoin is Ethereum, can you say it is losing its value. Another is BNB can you also say it is losing its value?. There is no argument there is always a time when the market dumps and all coins not only major altcoins will be hit but what signifies or shows how valuable some coins are is their ability to regain their price when there is a positive growth in the market. Ethereum for example dumped but this year it has regained its value although not as expected, but better than it was. Therefore, in my own way of doing things, Ethereum as a major altcoin is good for long term.