Well I consider investing in Bitcoin like a long straddle (options strategy). If it rips to upside or downside, it will do better than altcoins. Altcoins tend to be like the short straddle position: If Bitcoin stays still, they tend to do well (except with much higher upside than short straddle so I guess that's not the BEST comparison but whatever). As dominance declines, I tend to it increases the ferocity by which Bitcoin can recover relative to alts when it dips or rips. We'll see how that plays out if Bitcoin has another huge volatile pump or dump.