As far as I'm aware, the current accepted theory regarding the lack of wear is that the bows were new, recently issued as government weapons, supplied in the crates and had yet to have been shot. That theory works in tandem with the number of bows (over half!) with reflex in them. Steve Stratton I think believes that the reflex is just a result of the re-drying process, as the sapwood has a different drying speed to the heartwood and pulled the bows towards the back, but I'm not sure how widely accepted that is. Either way, almost none of the bows showed any sign of string follow or set, and that plus the complete lack of any wear does suggest a brand new bow.
Interestingly enough, if the arrows are made well enough they don't do an awful lot of damage at the pass of the bow. A lot of people for some reason bind their fletchings with thick linen (I think Richard Head's videos are to blame for this!) which of course once varnished/glued etc is a might lump which can gouge out the soft yew, but no records of linen whippings have been found, it was always silk. If the fletchings themselves are cut properly, and the ends facing the arrowhead are burned with a hot tool and pressed hard into the arrow shaft, then whipped with thin, strong silk you get an almost perfect transition between shaft and fletching, and shouldn't gouge too much out of the bow at all.
