This is exactly how I make a living, for the last 5-8 years, depending on exactly how you count, and some clients will indeed pay 10s of thousands for software

This is exactly how I make a living, for the last 5-8 years, depending on exactly how you count, and some clients will indeed pay 10s of thousands for software that they can't otherwise buy. It helps to be in a narrow industry, of course (mine was digital gold currencies, though I'm no longer doing anything in that market).