I think organic is the worst word to be honest. In terms of football philosophies and proven ability they're at opposite ends of the scale, Moyes and SAF. And how can there be a long term with a global excess-of-success fanbase like theirs? 99% of them will scream "Moyes out" if he doesn't deliver immediately, in my opinion.
The thing I never understood about the whole "Moyes does well with little money, so imagine what he will do with lots of money" line of thinking is that it's a completely different thing. Moyes' had a few expensive buys here and only Fellaini will go down as a good one, but to be fair I accept that's perhaps a debatable topic -- after all he was supposed to want Hazard, Moutinho and Dzeko years ago, who'd surely have been seen as good signings.
It's speculative, at the end of the day. It seems a gamble for them, and that in itself if why I think it's so crazy. They could have plenty of managers who are more attuned and accustomed to experiencing and delivering the success they'll demand.