22 Long Rifle was named for its intended purpose (rifle ammunition), giving us the 22 Long and the 22 Long for rifle or Long Rifle.
We speak in a fairly sloppy fashion today, though we used to write beautifully.
I believe it's correct, that it was, originally ".22 Long, rifle" or .22Long (rifle)..
I also think this is also how we got ".45 Long Colt" into our vocabulary. Not from the maker's official name, but from the commonly used name, when being bought over the counter. "give me a box of .45 longs, ..Colt..." is the kind of phrase I would expect to hear, which, over time became .45 Long Colt.
(sorry, no proof, just my theory)
And a few makers, put the "popular" name on their product. So, you can find (a few) boxed of .45 Colt, marked .45 Long Colt. Likewise, at least one gunmaker lists their magazines as "clips". They know full well that they are magazines, not clips, but they list them as clips so the customers who call them clips will find them, and buy then.
The .22 Long uses the same 29gr bullet as the .22 Short. Stevens took the 40gr bullet from another (and now long extinct) .22 rimfire round, and put it in the .22 Long case, and the rest is history.
The reason your almost never see .22 Long ammo on the shelf is because there is about zero demand. Not sure when they stopped making guns for the .22 Long, probably over a century ago, maybe before, as the Long Rifle gives more performance, and everything that chambers the LongRifle, will chamber and shoot Longs, (and shorts) as well.
you still see .22 shorts on the shelves, here and there, there are still guns made for the .22 Short (only). Not a lot, but they're out there.
Guns for the .22LR shoot shorts, longs, and LongRifles, though some .22LR guns won't feed shorts, some will, and some can handle all three intermixed.
Today, generally most people think of the Long as the Long Rifle with the Short's bullet. and that is essentially an accurate description, though it doesn't explain that the Long came before the LR, not after.
A .22LR with the .22Short bullet?? what's the point of that?? Today, very little. So, very low market demand for Longs, so very rare to see them taking up space on the shelf that could be used for something that actually sells...
You might find some on the shelf of the old mom and pop hardware/general stores (if you can find any of those still around - check SMALL towns in remote areas), where they've been sitting for 40 years. If you're really lucky the granddaughter working the cash register will sell them to you for the price marked on the box!