Never: First rule of marketing is to be in people's mind as leader or coleader.
Humans mind has just place for 3 name of each category: Leader, Coleader, Cheaper alternative.

Coca Cola - Pepsi Cola - Anyother
Redbull - Monster - Anyother
And so on.

So in crypto it comes as
Bitcoin - Ethereum - Anyother.

Bitcoin will last forever in people's mind as the cryptocurrency n1.
Like facebook does as social.
Like youtube does for video.
And so on.