BTC dominance just hit 60%. Here's why that number matters more than Bitcoin's price right now. Dominance measures BTC's share of the entire crypto market cap. Think of it like oxygen in a room — when Bitcoin absorbs it all, altcoins suffocate. But 60% is the historical ceiling where one of two things happens: BTC breaks above and alts bleed harder, or dominance rejects and capital rotates into al…