I don't think it is stoppable. If the old bitcoin protocol become outdated, it is up to the team to come up a new bitcoin protocol, and port the bitcoin holding records and wallet addresses to the new one. It is a blockchain based ledger, like a notebook. So if the old notebook run out of pages, simply create a new one and port everything to the new notebook. Hard fork, soft fork, exchange coins and etc, it is a free market.