Here's why alts/btc pairs tend to bleed over the long run:

BTC generally has +ve average long term inflows and Alts have negative inflows on average from: VCs, Team, Advisors, etc.. dumping.

But, we get infrequent spikes of demand inflows from alts whether it'd be from narratives, rotations, etc.. which will cause the Alts/BTC pair to wick up significantly

This is because the liquidity in the orderbooks of Alts orderbooks is extremely thin which leads to huge % changes in price. Even if BTC does go up alongside the alts, given the thickness of the BTC orderbook the Alts/BTC pair will still tick much higher. 

cr: kwaker_oats_