that strategy of buying both chains means they will lose money at some level when the dominant chain eventually wins.
Look at it not as individual assets but as a global ledger. If the global ledger represented by the combination of both (temporarily viable) chains, then if you buy say 1% of both chains, and one chain dies (goes to zero), you still own 1% of the global ledger. Any value that disappears from your coins on the losing chain would be redistributed to your coins on the winning chain.
I'll comment on the other points later, kind of busy now.
maybe.
lots of moving parts in that one that could invalidate the assumption. for starters, constant forking like i've described could decrease the value of the entire network from the getgo.