Doctors know what causes a certain disease. Investors know that hardware margins are small. Social media experts are aware of the huge install base of Pokemon Go. Cable operators know that an onsite visit to a customer costs a fortune. Even this presentation designer has argued many times not to preach to the converted, it is better to spend time and slides on issues that are less clear cut or controversial.

I still believe this is true, but I would not go as far as completely eliminating the obvious point from your presentation. This will break the flow of your story. Also you miss out on the opportunity of using the same visual concept for both presenting the (obvious) problem and your (not so obvious) solution.

A place holder slide with a simple image or statistic is enough to remind the audience of the obvious in 20 seconds. 

Image from WikiPedia