I hand load for the many reason that have been mentioned above. Yes, some of it is to be cost effective especially when some of the calibers I shoot are 318 WR, 404 Jeffery, 425 WR, 416 Rigby, 450 Nitro No2, and 500 Jeffery. Cost aside, I believe all hand loaders would say the ability to select their favorite bullet and work up loads for their rifle to obtain the best accuracy and performance is the main reason we do it. What a rewarding process to develop a hunting load and reap the soils after a great hunt.
Yes, you can take plenty of game with a factory load, but the satisfaction of putting the components together, practicing with your hunting load, and finishing with a successful hunt is why I hand load. A hand loader always relishes the recovery of their bullet from the harvested animal to see how it preformed and to later to drop that bullet on their scale in order to determine overall weight retention. I do not know if the hunter who buys his ammo derives these same pleasures.
With the numerous quality bullet manufactures today, vast calibers to choice from, and vast amounts of load data, I cannot help but want to hand load. I read on this very forums 25 pages of people speaking against Hornady ammunition. Here is my response: load your own ammunition. There has never been a better period to become a hand loader, and it is never to late to start.