If Drivechain doesn't get soft-forked into Bitcoin, the alternatives people are left with are:
- Altcoins. People who want super-powers (privacy, smart contracts, cheap transactions) move their stake to shitcoins. This doesn't make much sense because even if altcoins had the necessary technology they wouldn't have the base money with which to use the technology, but still this remains an option.
- Fully-custodial and trusted systems. Instead of moving their money to a sidechain secured by Drivechain people can use a centralized service with much less safety and subject to all kinds of regulations, hacks and government takedowns.
- Federated sidechains, which are the same as custodial systems, but with distributed trust and maybe less, maybe more government involvement.
- Less secure sidechain-like constructions, like sidechains secured by a multisig of a fixed set of entities with names, or BTC tokens in other blockchains guaranteed by a collateral denominated in shitcoins which tends to zero.
- Corporate takeover. Big banks and giant corporations start buying all the coins and exposing part of them through their closed systems to normal people. Instead of an open network and free market as everybody expected, all meaningful activity now happens inside these legacy evil entities that are already sold to governments from the start.
Every time one person goes against Drivechain without proposing something else better, they're condemning bitcoiners to one or many of the above forever.