This is very necessary if at any time there are obstacles from suppliers such as the Corona case now, so the store can still operate by selling print on demand products and setting all imported Alidropship products into out of stock.
So your store can still operate. Not everyone sells print on demand stuff as well. So the majority of people would not have the desire to do something so damaging to their store's reputation. If I visited a store that had every single item out of stock (except for some print on demand stuff), I'd never return to that store again. It's a great way to lose customers. Forever.
Just telling you this because with all the other suggestions waiting to be acted upon here, this one may be pretty low on the list and you may be waiting several years. Perhaps even forever. In that light, if I was you, I'd be thinking of an alternative plan. (Like I suggested in the other thread.)