Amen...to that. I posted a few links to check out before the election, and even a few afterwards that still had stock and decent ship dates and prices. You might try searching back a few posts for the links.
Other than that, it is as you say, pretty much hit or miss, and even when you do hit a site that has something, as you've found out - sadly, some are taking advantage of CAPITALISM
But then again, do you blame them? We all sat around fat and happy when there was no ban and lots of stock to choose from. A bit spoiled ya think?
Even when the candidates were still running, the alarm should have gone off in most of our heads. Sure a few thought no way, the ban is over, no sweat, no worries

And then the unthinkable happened (well, at least for those who thought no way could he win) and the ban threat reared it's ugly head. PANIC buying started and got constantly worse. On the flip side, what an instant boom to the economy - at least for the gun and ammo manufacturers.
Now, you can still find the parts, but you'll have to do a bit of searching, and finger crossing. I was able to pick up some mags recently, and that was even after everyone seemingly picked through every nook and cranny buying everything and anything in sight. Parts kits, receivers, etc. will be a bit more challenging, but the most challenging of all seems to be -----BARRELS. From all the distributors I've talked to recently, they are sitting pretty well on the parts, they just can't get barrels fast enough to fill all the orders, not just for complete guns, but upper assemblies, etc. So learn from what you finding out now, do the extra searching, maybe stray from all the major sites, and do some searching for the lesser known ones. Sure it's a gamble, but it may pay off if you find what you are seeking. When you do find your parts, you may want to consider picking up a spare or two, depending on what you think you might need, and please...feel free to share the find with the rest here. At this point...we're pretty much all in the same boat.
Slo