Although I have yet to "wear out" any of my all wood bows, be it selfbow or composite, IMO, all wood bows DO have a life span and many factors go into determining that span. This includes how well it's made and design considerations, how one goes about shooting the bow (your style), how much you shoot it, and even climate conditions. They are less than perfect, and that's why bowyers keep trying to come up with better. That being said, they have their own "coolness" factors that draw us to all-wood bows. A yew selfbow, for instance has the properties in the sapwood and the heartwood to create magic, when designed correctly. Osage is resilient in it's own right and can overcome many flaws or limits in design to shine above almost anything.
A composite bow of all-wood, really is an attempt to mimic what yew already has, or what osage can do. It solves some problems, but has it's own inherent idio's....and looses a bit in the "coolness" by being engineered instead of natural (IMO). But it is still very cool to make it yourself, and can be thought out and manipulated a bit in it's design and construction to build in "last-i-bility", I think. Also, if you are learning....composites can be cheaper and tons of fun as well.