Yes, its a bit like asking. Imagine there was a massive EMP strike that hit the entire world and fried all electronics.

It would be a total disaster and yes probably 90% of the population would die. HOWEVER, our rebuild would be much quicker than the ~200,000 years it took us to get here. Because we now know that electricity, lights, telephones are a thing. Building a telephone is 100x easier than discovering the concept.