When pitching your startup it is a waste of time to dwell on educating investors about things that you can pick up by reading the major tech blogs: smart phone penetration, sharing economy, etc. etc. A smart investor is likely to read the same posts as you do.
Put in a place marker slide to make the generic point in 10 seconds, then move on and explain why your particular application of the sharing economy (or another major trend) is so innovative and clever?
If the idea is good, you might convince investors of this point as well very quickly. Then, we move into the territory if you, your partners, and your plan to make it all happen. And that is the toughest part of the pitch. Not from a design perspective (it is easy to draw a few Gantt charts), but the difficult bit is getting your plain straight and convincing investors that you can pull it of.