I can reload .32 Longs and 38 Special now cheaper than the cost of 22 LR.
For that matter 9mm. Cost to handload 9mm and many other small pistol rounds are about the same. If one has unlimited amounts of brass and ample amounts of casting lead then of course 38 spl (or any other small pistol caliber) would be less expensive than today's cost of 22lr.
I don't have any experience with AR style rifles chambered in 9mm but have seen others at my club shooting them high volume style like those who shoot rimfire AR style guns. But still, if I could load 500 rounds of 9mm at 8 cents/round I would still rather pay 10 cents/round to purchase ready to shoot ammo in my hi capacity semi-auto firearms.
If I stop at an LGS right along the way home from work and pick up a brick of 22lr for $50.00, I have no time (labor) or shipping costs invested in my brick. Cost per round is 10 cents. If I handload 500 rounds of 9mm on my progressive press, it will take me an hour at least, not to mention my time casting, cleaning/prepping brass, buying primers and powder and so forth and I might get the cost down to 6 cents/round. I have to use literally thousands of dollars worth of tools and eat up utility costs which handloaders never seem to factor into their ammo costs.
I guess what I'm getting at is if you shoot pistol ammo at 50 to 100 rounds per outing then 38 spl handloaded would be less expensive than 22lr. But if you shoot high volumes of pistol ammo, the high cost of 22lr might still be worth it. I'm sure the cost of 22s will someday come down to more reasonable prices.
Don't get me wrong, I'm a committed handloader. I try to convince myself that loading my own 9mm is, at a cost to me of say 16-18 cents per round, is better than paying 32 cents/round of factory 9mm. But if I got down to the nub and figured out my real actual cost per round and factor in my time spent handloading, I might go back to factory ammo. The main thing for me is I have high quality ammo available to me in high quantities and have no cares if there is any ammo shortage, I can shoot on and on.