If you've ever seen factory .45 Long Colt cases of 100 or more years ago, you'd realize why it was never put in a lever-action rifle - just the barest example of a rim.
Back in the 1970s I reloaded some old Remington .45 LC cases that had this tiny rim. The shellholder pulled right off the rim with the slightest nudge.
I can't imagine the extractor of the Winchester 73 or 92 trying to grasp that little bit of rim and trying to pull it out, especially in chambers pitted by corrosive primers, black powder and a thorough lack of cleaning.
I'm sure Winchester looked at the feasibility of chambering to the .45 Long Colt but decided against it. They had everything to lose and nothing to gain by not chambering their rifles for the .45, but they also had to think of their reputation for reliability.
The average owner of the Winchester would have blamed the rifle, not the cases, for any malfunctions. Oliver Winchester was too smart of a businessman to risk his company's reputation on that.
Frankly, I can't understand why the .38-40 was ever adopted. The difference between it and the .44-40 are nominal -- a .40-caliber bullet vs. a .430 bullet. Only 3 calibers of difference hardly seems worth the effort.
The more I use my reproduction 1873 Winchester in .44-40, the more I realize that the old-timers were well-served with this rifle. It's accurate and that soft lead slug really flattens on impact. It's not a good choice for anything larger than deer or antelope. It's also a good defense rifle, even in these days.
My Uberti holds 13 rounds in the tubular magazine and I can crank them out quickly and accurately, accurately enough to hit a man out to 35 yards without pausing to align sights.
Here again, that 200-grain flatnosed slug at 1,200 fps is not to be sneezed at. It won't penetrate Kevlar, but I doubt a man could remain standing after taking a center-hit in the vest with one of those big bullets.