Easy - give him 4 mil in equity.

On the other hand if the company doesn’t have good prospects, then indeed there is nothing you can do.

Personally I would rather take cash.

You would likely think differently if you cared about the product and had invested time in developing it.

Having said that, there is no evidence their developers felt differently to you.

I do almost nothing but develop products. However as product becomes mature I start looking for new things to do. Also maintenance of mature product requires different type of people, not inventors.

Obviously this isn’t how Anders Hejlsberg, who invented and then ‘maintained’ C# for a decade thinks about things.