The big deletion wouldn't work at getting rid of information because there are too many ways at maintaining information without having networked technology.
Humanity wouldn't just tumble all the way back to the stoneage, we'd go back to right where we were before the interstellar age where there are plenty of ways to record information. When you walk up a hill you don't trip and fall to the bottom of the hill, you roll down and stop somewhere between the top and the bottom.
I maintain, it is LAZY attempt at a cure all. The Big Deletion was only used to make people forget that Aliens had been on earth in the EU. That is the problem. Had they not been on Earth you could have used it more effectively. As it stands within 200 years where the Aliens are still on Earth in the first place its just about the most half assed attempt at a reboot for a franchise I've ever seen.
OK guys, we will just have humanity collectively forget about the Aliens that are still running around on earth, because of a technology issue.