I believe that it was just a mistake. There were many cartridges that are perfect for their individual uses, and in a sense, IMO, there are no particular situations that would call for this round to the exclusion of others. To a certain extent, or there are a half dozen other alternatives that will do the same job as well or better, at least in the past, a cartridge had little hope of survival. History is littered with marginal cartridges that just didn't fly because people wouldn't recklessly buy a new caliber on a whim, like we do now.
For example, we had the range of .44 magnum to .444 marlin to .45-70, and mankind at large was pretty happy. No need for a dozen different .40+ bore rifle cartridges.
The market for lever rifles has always been huge. I suspect that people just chose to go for the real large bore when offered a choice, and got 45-70. I know that my brother in law did, and my other BIL went 30-30. No in betweens. Funny, the one with the 45-70 bought it for deer, and the other actually hunted with a .44 magnum for deer for many years.
I SUSPECT THAT IF ANOTHER COMPANY BROUGHT OUT AN EQUIVALENT ROUND, ENGINEERED IT RIGHT, MARKETED IT WELL, AND IT GOT GOOD PUBLICITY, IT WOULD FLY OFF OF THE SHELVES NOW.
People are more affluent than they were 40 years ago, with more (ostensibly) disposable income and are willing to spend maybe twenty times as much each year on guns and toys than the average hunter did during the 60s and such. No more families with an 8 gun cabinet with empty spaces in it. I'm sure that a heck of a lot of people here have twenty or even 40 space firearms safes at home that cost $2-3,000, and this sort of prosperity and discretionary income is what decides whether a cartridge, or even company survives. When my father died, I carried home almost 20 half empty boxes of 30.-06. He sighted in, he hunted, he had dinner for a few weeks. Then he got a new box for the next year.
When I was growing up, leupold was kind of a marginal company, made great products and they were very popular, but their sales volume was low. Only a half dozen companies really ran the entire optics market. Eight feet of shelf space ran the entire department. Look at the scopes available online or in a mass store like cabelas, and you'll see what I mean. The market is huge now, and very diverse, and when that round was released, the market was pretty small and insular. I know people who own a half dozen AR rifles. I know one who is so crazy that if he had a chance, he would buy an AR in .375 winchester just because he could hunt black bear with it.