If he had a Windows version it should be able to make enough money to pay for a support person AND still be incredibly profitable. He just needs to have someone

If he had a Windows version it should be able to make enough money to pay for a support person AND still be incredibly profitable. He just needs to have someone else do the selling in order to let him focus on the hard technical problems. That being said, the market for a Windows version should NOT be individuals, it should be marketed to the enterprise. Tarsnap solves a problem that many companies have and pay buckets of money to cure.