Bitcoin block rewards shrink as we know, but soon like 6 years it would be feasible to consider the transaction fee making up a significant part of the block reward. moving those fees to a SC would degrade Bitcoin.
Miners mine both chains. They profit no matter where the transactions take place.
I mine, i used to MM NameCoin, i dropped it because it wasn't worth the effort and the 2% pool fee i sacrificed on by BTC. nameCoin's fate could happen to Bitcoin, also 14 years form now we may choose to drop bitcoin altogether because its not needed anymore, it worked as a seed for the SC's.
I'm sorry but this is a very, very shaky parallel to make.
If Bitcoin is not needed it is only because a better store of value will have appeared. If it is so then let it be, but I don't find it likely since Bitcoin has worked exceptionnaly well so far, benefits from a considerable network effect and has very sound fundamentals.
I'm going to quote Justus again
Currencies only have value if people use them, so there is no way for Bitcoin to have / behave as a store of value in the long term except as a direct consequence of its use as a medium of exchange.
.... Bitcoin would lose out to a competing currency with less/no rationing that would be less expensive to use for settlements.
High transaction rates on the main chain are the only way for Bitcoin to survive.
Metcalfe's law was my way of thinking about it, I'm happy for something better to come along, i believe bitcoin is a better store of value because the the economic energy maintaining the ledger stays in the ecosystem. as soon as bitcoins move into a SC the SC benefits with no downside risk, the locked scBTC has no value as the value is in the SC tokens. if it goes bad just get a computer to refund your BTC, if it succeeds then the value is gone for good it resided in the SC, theoretically you can convert it back but why? it seems to me the more SC grow the less valuable BTC becomes.