To add....the tightness of the grain has a lot to do with it. That why hard rock maple is usually used. It grown in northern areas, grows slower, so it has tighter rings in the tree.
Musicians that play violins seek a Stradavarious. The wood used was grown in the dark ages and has a very tight grain.
Wrong. The reason those instruments are so highly sought after is what happened to the wood before I was crafted into an instrument. Back then water ways were used to transport everything. The nice thing about wood, it floated. The bad thing about back then, no EPA. There were chemicals in the water that were very hazardous to a persons health. But those same chemicals absorbed into the wood, transforming the cellular structure of the wood. It made the wood produce a lower, richer tone in comparison to other makers.
As for shafts, yes they can go bad. Even though shafts are made from hard rock maple, it's still soft. Through usage the shaft will become compacted. It's why it takes years, 10+, of using the same shaft daily for it to 'wear' out. But the shaft doesn't go bad, it just becomes stiffer and plays different.