I guess he doesn't look at charts. If he did, he'd see that that's the exact opposite of what has happened in every bull run. Historically altcoins increase in overall marketcap when there's a bull run, which obviously means bitcoin shrinks. I think it shrank to under 40% in the last bull run, so 25% wouldn't be out of the question in the next bull run if the long term trend stays as it always has. Maybe he got confused and meant in the next bear market as the market consolidates to bitcoin because noobs realize they have no clue what they're doing and buy what they think is "safe".

What will be interesting is if bitcoin drops below 25% of total marketcap and a new leader is crowned, do noobs still think bitcoin is the safe choice when the next bear market rolls around...