In a pitch there is always pressure to keep things as short as possible. It is therefore tempting to compress the problem you are solving is as few words as possible: "[x] is not very flexible", because hey, people know this, right?

I tend to drag out the problem section of the pitch a bit:

• Remind people of the problem in an emotional way, that they "feel" it, usually with a picture or a statistic
• Point out what is the cause of this problem, it is often soften very trivial that people did not realise. ("Did you know the reason is that there are no batteries light enough to do this?")
• Point out why it is so hard to solve the cause (not the problem itself). ("The law of physics that you cannot have this, and this at the same time)

Now you have set up the audience to show why your solution is so clever.

Image: Wolfgang Pauli and Niels Bohr demonstrating 'tippe top' toy at the inauguration of the new Institute of Physics at Lund; Sweden