If you think the startup is failing it is either because a.) the startup is actually failing or b.)you don't believe it can be a success and assume it is failing.
Either way it doesn't sound like you are passionate enough about this startup anymore.
So the real question should be. Should you continue to work at a startup you have no passion for? The Answer is NO. Change jobs.
So the real question should be. Should you continue to work at a startup you have no passion for? The Answer is NO. Change jobs.