Software is meant to be used continuously forever and ever. I have some exchanges that I programmed that are 15 years old now - still working peacefully ( the benefit of using PICs - they last forever). The company is no longer in business but with a soldering gun they manage to keep them operational.

So the real question is not only why should I pay you, but what happens when your company goes the way of a cockroach treated with raid. And don't tell me you are market leader - we see them raise and fall 5 times in a decade.