I was looking for a chart of that actually, what is your source? My point was also, a big chunk of alts do not have a super liquid market, makes it hard to count them seriously in all aggregate market cap.
I do of course agree with your overall conclusion - Bitcoin is still the most dominant, it just doesn't have the majority of market cap (since late 2017)
What? It's over 50% of total crypto market cap. And a huge chunk of the altcoins are barely liquid.