This is kind of ironic for me, because i bought my mini 14 about a year ago and my logic was "its .223, you can find it everywhere no matter what. Its also the cheapest centerfire round out there"
I have been proven wrong.
Long term I don't think you were wrong at all. This is just a bump in the road when you look at the big picture. The common rounds, 223, 9mm, 30-06 etc. will still be the easiest to get if you think long term. This happened in 2008 and the same thing happened.
At the start of panics like this the most common chamberings go first. We are in the middle, hopefully nearing the end. There are still some less common ammo on the shelves, but in very limited quantities since there was never a huge demand for them. As the panic buying slows and eventually ends the common rounds will be back on the shelves 1st and in the greatest numbers. It will be a long time before ammo makers have time to think about switching over to making some of the less common chamberings.