At this point I have no other expectations than hoping the product scales as has been envisioned and solves the problem at a meaningful scale to justify the 4 years I have put in. I'll figure out the money part somehow or just go broke and get another job.
You've already justified the four years you put in by doing much more than your share of the work to keep the company going this long. Nobody can fault an employee for leaving an abusive employer to pursue better opportunities.
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.