Well, perhaps. However, with selfbows you're dealing with an organic material that often behaves unreasonably. Sure, the better bowyer will know what pitfalls may lie ahead and subsequently how to avoid them. He (or she) may also be able to better read just what kind of bow that particular wood species and stave/billets can safely produce.
However, traditional bowyery, just like traditional bowhunting, is about taking advantage of opportunities presented. I've seen a lot of fantastic, A+ bowyers have a mess up now and then (which is why you said "much" I think!). With laminated bows you have much more control. Selfbows are wild little creations with so many more variables that sometimes give unexpectedly. It's one thing to have a bow break from a poor lamination glue-up...selfbows are often another story. If that tree was supposed to bend like that it woulda' grown that way. The way I see it, a great bowyer is anyone who can take that tree and "mess it up" and then "fix it" into doing something it wasn't designed to do.
But, you're main point is much needed....HAVE PATIENCE!!!!!