You don't have leverage. You know they couldn't get software as good as yours in a short time, but they don't know that.
Companies always drastically underestimate the cost and duration of software projects. They'll see your 2 years of nights/weeks and turn it into 3 months in their minds.
There is simply no way to get to the same product in 3 months. There is a lot of business complexity that has been worked out over years of iterations and experience.
Companies always drastically underestimate the cost and duration of software projects. They'll see your 2 years of nights/weeks and turn it into 3 months in their minds.