It will most likely involve mining at a loss if the current percentage of hashrate support stays the same and the current cost of futures matches the price when the chain is created, but you need to point out these assumptions to make a reasoned argument.
The very second a miner starts mining at a loss it means he has a hidden agenda. Isn't it strange to you that Coinbase has put this arbitrary "48 hour limit" to decide and stick to what they will be listing as BTC? It sounds to me that they have the money to mine S2X chain at a loss for at least 48 hours, then they could be able to stop the bribing and keep listing S2X as BTC and then point at how they followed what they said they would do.
Bitcoin has the potential to become worth several trillions. A government would sure find incentives in having people like Jeff Garzik (bloq) as the main dev of the main branch of the software so they can make a call and introduce changes in the protocol that would benefit them. This is a war for power, everyone knows doubling the blocksizes solves nothing, and BCash is already out there for these that want cheaper transactions without caring about running an affordably sovereign node.
Bitmain has already threatened with attacking the chain before, this is not new, so you get ready for such an scenario before it happens.