It isn't the old days anymore, when who knows how many rolls were sold through pharmacies and corner stores and groceries to people who didn't know they could get it cheaper from B&H (even pre-Internet, I used to order from them pretty regularly, just pick up the phone.) Now film shooters, especially black and white, tend to be pretty serious hobbyists and everyone knows how to use Google. Tri-X may still be Kodak's best selling black and white film (I hope so, it's certainly my favorite of what they have left.) It doesn't make any sense to dump it at cost to a store that will re-sell it to your core audience half what the branded product costs. You're just undercutting yourself. Ilford apparently figured this out too - remember when Freestyle sold all the major Ilford films in cheaper store brands? I do. In fact I have an unopened but poorly stored probably useless 100' roll of "D-Max 400" that everyone knew was Delta 400.
Of course not everyone who shoots Tri-X and is online knew that Arista Premium is Tri-X, but it doesn't take much looking to figure that out, even accidentally.
I'm glad Foma will continue, I don't shoot it in 35mm but I do like getting cheap Foma in 120 to try out cameras and developers and generally experiment, and in 4x5 and if I ever go 8x10 the price is appealing. Hopefully they still make money on the Arista branded films.