Who said ETH lost? There is no story that ETH already lost with other altcoin. ETH still top 1 altcoin based on coinmarketcap
But people just need other altcoin because there is no room for everyone to use ETH network.
Yes, no one has been able to beat ETH yet, if there is a statement that ETH has lost it is just one, we can see ETh's position is still the strongest among many altcoins on the market, and it's true what you say, ETH doesn't have room for everyone , people will choose other coins to invest because they can't afford to take a place in ETH, and that's a bad bad thing other coins also exist which have great potential to grow.