I've seen guys go from barely able to say hello without getting their tongue tied up to being able to pull in 6 figure deals without breaking a sweat (contract work, web development), I really don't know this guy at all but he's already selling, all he needs to do is to improve what he's already doing.
Going from 'not being a salesguy' to 'being a sales guy' is a lot harder than going from 'being a not so good sales guy' to 'being a salesguy that is a bit better'.
Even an experienced salesperson would have a hard time selling a product he has no experience with, and that has only just been 'baked', they should have overlapped much better with the development but this product seems to be 'all or nothing' so that may have been harder than what we know from the info given. Building up a sales pipeline takes time, and as you sell a couple of times you usually get better at it.