They didn't foresee this, and that's on them, sure. But their response to this, given the situation, is just about the best I could expect from them given the circumstances.
Would it have been better if the next operating system update already shipped a fixed store rather than another broken one? Sure. Would it have been even better if they had the ability to remotely fix the store on the many millions of already online Apple devices? Absolutely. But if they couldn't do either of those things, which seems likely at this point, this is the next best thing while they get the rest of their shit in order.
I don't think it's particularly constructive to point out how everybody else has already been able to patch this in all places. Apple's clearly in a spot right now. Blame them for that, but don't blame them for picking the best option at their disposal right now.