Take the following quote:

"Everything that can be invented has been invented." -Charles H. Duell, Commissioner, U.S. Patent Office, 1899.

Now, if you Google the quote itself, you'll find that a lot of people are pointing out that it cannot be confirmed that Charles H. Duell, or anyone else at the U.S. Patent Office, ever said this. They mention that it's a cute quote when you consider the source, but the attribution is either mistaken or it's just made up.

Does it really matter who said it, or, for that matter, if anyone ever said it in the first place? Who cares? The reason the quote continues to appear inside of most "How to Patent Your Inventions"-type books that are written is not because people expect it to have been verified but because it inspires. It reminds us of the timeless truth that most of us have a myopia about what we can dream up to solve our problems.

If you really refuse to be inspired by the quote above because you can't confirm that it was ever uttered, here's a web page that lists several similar quotes from which you could draw inspiration.

Things People Said - Bad Predictions

Pick the one you like best and run with it. I think the overall message is that you shouldn't make any assumptions about what your audience doesn't want.