It sounds like that “bad” code was good enough to provide enough business value to keep the company going and you employed for at least 2 years, so I’m not sure

It sounds like that “bad” code was good enough to provide enough business value to keep the company going and you employed for at least 2 years, so I’m not sure your assessment is accurate. Maybe you mean “destruction of value” in terms of opportunity cost, but that’s much more abstract and very hard to truly measure. Businesses run on cash flow like blood. Once the cash stops, it dies right then and there. It doesn’t matter if a better design will only take a few more months if you can’t make it to tomorrow.