I think it might have been plausible given slightly different reasoning than "oh lets just make a fresh start of it".
Using the reasoning given it was stretching it a little imo. You wouldn't think that 38,000 odd people would all be in complete and utter agreement to discard so much technology that, 150000 years later, we have not found a single trace of it.
This is another point I forgot to bring up. And since they all spoke one language (English I presume?) surely all the languages on earth descended form one language? It's funny because that isn't what historians and linguists say. What a contrived ending.