My opinion is don't wait until the sky does fall, which it most assuredly will. Both entities will be around for a few months at least, maybe longer, before they begin the transition. So buy what you can, while you can.
Just took my own advice. Yes, I have plenty of tobacco that I enjoy. No, I didn't need to do this, but one of my favorite blends, St Bruno, doesn't age for shit, as I found out when I opened my tins and pouches from 2016 through 2018. This is true for the Mac Baren version. The Ogden's version, even when it's decades older, will still have more flavor in it that this stuff, provided that it has been cellared properly.
Don't get me wrong, the Virginias are OK, but all of the toppings have died out, so it doesn't taste like St Bruno in the least. The plastic pouches of the flake, that I bought from Estervals are marginally better than the tins I bought domestically, but only marginally. The topping is kaput. But then again, MacBaren didn't lay enough of a topping to the flake tobacco when it was new. So I bought the ready rub version, which is MUCH better than the flake, IMHO.
The other one was Doblone d'Oro. The current version isn't bad, and I don't yet want to dig into my 2014 and 2015 stocks from when it was a true Three Nuns clone, the only one that's come close to the real McCoy, something which changed by 2018 when MacBaren changed the blend. So, I ordered a couple of tins of that. Not cheap, but...