Interesting thoughts but I think "the sum of transaction fees people will spend in the future" is better as a value for mining (after rewards go to 0). "Holders" really aren't wanting anything to do with transactions.

My Bitcoin valuation:

Bitcoin is worth as much as it costs to move to another blockchain.

That's the "first-mover advantage" basically and I'm afraid it's much closer to $200 million than $200 billion.