Actually Boddington did mention dropping the .30-40 Krag (see his list posted earlier). As for the 8mm, here is his reasoning... "We could easily discard the 8x57, but I've already done away with most of the cartridges that use it as the parent case--6mm Remington, .257 Roberts, 7x57. Better keep the old 8mm Mauser so we'll have some brass!".
A reminder that the premise of Boddington's argument is NOT to take these cartridges completely out of circulation, but rather for manufacturers to concentrate their efforts on the more popular cartridges. The balance will be picked up by handloaders.
His explanation follows:
"The reasons why I have chosen these cartridges vary tremendously. A cartridge doesn't have to be bad to be unpopular! Some are truly obsolete, some are great cartridges that just didn't make the marketing grade, a couple should never had existed at all, and some are only viable in handloaded form--so why bother with factory loads at all?".
"By the way, just because a cartridge is popular doesn't mean that its great, either--but I've avoided truly popular cartridges because they aren't going to be culled. I didn't attempt to take into account why a cartridge was popular. For instance, you won't see any of the old-timers revitalized by Cowboy Action Shooting on my list.".
"In setting my rules, I've also stayed away from proprietaries. If a gun company wants to foot the horrendous R&D costs to have their own unique cartridges, that's fine with me. Likewise, if the consumer wants to buy them and deal with single-source availability. So the only candidates I considered are cartridges loaded by a major U.S. manufacturer.".