For most people barrel life that short is a consideration especially for the minimal return.
Not everyone can afford the time or money to buy, load for and shoot multiple rifles in different calibers to let a real "barrel burner" rest so to speak between seasons.
The Rum was a great idea in it's time but it burned out quickly because of the high price you pay in money, components, barrels, recoil, and muzzle blast.
With all of the Rum's it's easy to find two kinds on the used market. Those that were shot less than 20 times before the owner said, "I can kill game without abusing myself", and those that are shot completely out.
If a dragster is what someone wants and they know what they are getting along with all the costs more power to them but I've seen a whole lot of guys waste a whole lot of money and then lose their butts trying to sell a "barely used" boomer that was just too much for them to handle or enjoy and even more that were badly disappointed when the rifle they spent so much money on and all the time to work up loads etc only to have it burn out ridiculously quickly.