I think the key which is often missed is that for holders who are not spending time on exchanges but holding long term the BTC only value includes that of BCH and BTG :D
Also interesting point in regards to the coin cap and recent pumps. Funny how people gravitate toward a "whole" coin. Wondering when Doge will re-enter the top 10 now, lol... but kinda serious... Doge can do everything LTC and BTC can do - swaps and so on but has a huge circulating supply and releases the same amount every year; now we need segwit active on it. Not pumping it (only holding a few hundred I got for free when I mined LTC).