These metrics are interesting and important but may I propose another way of measuring who gets the crown; the chain that spawns the most new valuable hardforks. If I esiewert, decided to create a new hardfork years down the road, I would have to choose which chain to split from. I could bcash, bseg or bseg2x. By then the ownership on each chain could be radically different. I will choose whichever one I feel has the most support behind it and / or would be most responsive to whatever changes I propose. Eventually the market will decide on a particular chain as the 'base' from which other forks happen. Speculators will pile into this everytime a fork occurs that has any value, and this chain will have massive value.
This doesn't address the basis for network valuation. While price can remain disconnected from fundamentals for quite a long time, the fundamental value derived from Bitcoin and other cryptocurrency networks are the networks. Each fork is "splitting" from the original network.
In other words, with each fork, the legacy network is being cannibalized. Some users will stay on the original network, and some will start using the new network. In both cases, supporters of each respective network may dump the coins of the network they don't use. According to Metcalfe's Law, these types of network splits should significantly damage the value of both the original and forked networks, if the splits are considerable in size.