I think in the end, it comes down to economics, and that most people would have more than one bow if traditional archery is their main avocation and if they could afford it. Because of that, I would feel guilty advocating that a person have more than one bow, since I am blessed with adequate retirement income and can afford it, while many others who may be more deserving are not. You can have plenty of fun and hunt with only one bow, if it is a reasonably good bow that is reasonably well matched to your strength and drawlength. The nice thing about trad archery is that you can hunt elk, squirrels, pheasant, and fish, and also compete with the same bow, which would be difficult or impossible to do with one gun.
Having more than one bow affords you the opportunity to compare bows, and have a bow that is a little more specialized for each of the activities I mention above, or maybe to find that one perfect bow that suits you better than any other. However, from experience, I would also say that finding that one perfect bow is like searching for the Holy Grail, or that one perfect woman. Maybe it would be better to change yourself to better fit the one you already have.