that was not his argument. a simple SC with an innovation should be able to defeat the MC w/o the innovation once block rewards disappear. why? the risk free put and everyone taking advantage of the innovation to transact.
No, because a 1:1 SC with an innovation only serves as a subset of Bitcoin's money function.
Example :
An anonymous sidechain is only useful to those wanting to participate in private transactions.
A faster transacting is only useful to those needing faster transactions.
BTC, on the other hand, sit on the most liquid & secure chain, are supported by the biggest infrastructure, carry the most important network effect AND can move freely, back and forth, between the two aforementioned sidechains. The features are effectively user-defined and can be used at will, depending on the user's need.
I don't see exactly how the block reward is relevant considering there is no block subsidy on "a simple SC". Miners will mine both chains and profit from both chains' transactions.