Investors keep on insisting on simple and short pitches, cut pages, cut time, simplify. I don't think that there is a problem with the investor's IQ, there is not reason to dumb down your story.
What might be happening is that your business actually is very familiar to the investor. She has heard similar stories a thousand times before. A gig economy idea in a new market segment, a me-too business in a different country, a new Internet security technology, semi conductors that are a factor 10 faster, a new private equity fund that promises to be really hands on with portfolio companies.
While your business is new, the investor has learned 90% of the context in previous presentations. Talking 10 minutes about how successful Uber is and how this idea can be applied to other sectors is a waste of time.
Simplify/shorten your deck means: I understand already a lot, let's go to the interesting bit.