Will you be happy if the startup goes under and they've been paid and you haven't?
Take a step back and realize that your self-worth is not based on the success of this company's product and this company is not your life or your family. With your skills and the experience you've gained from this job, you'll find a new job at a better-run company that will have a better chance of releasing a successful product.
Also, if you quit and they don't pay you every cent you've earned within the number of days required by law, you can file a wage-theft claim with your state's labor department - they're very serious about employers ripping off their employees and will file criminal charges if necessary. There's absolutely no reason why you should go broke because of this company's mismanagement.