Because announcing there will be shortages is guaranteed to produce shortages.
I used to buy a sum total of six rolls of TP in 2019 (I use a bidet, so this is mainly for guests).
Right now I have a box of 24 in the house with two used all through 2020 + 2021 (no guests, that's why).
So that's 22+ rolls which I have taken off the market without utility, which is because the week I went looking for TP it wasn't there and you could order in bulk instead.
They pulled the lever on the trolley problem, therefore it is their fault, but not pulling is also a choice with damage.