Yeah, I wonder if that would be a good way to approximate the value of a platform like Ethereum. It becomes difficult partially because the price of Ether reflects the market's perceived value of the basic platform itself, given the fact that all of the tokens issued on Ethereum are valued what they are; that is, in principle, the possibility of double-counting has already been accounted for and the market caps actually reflect the reality.

Of course things are always more complicated than the basic principles would have you believe.