Why Prototype is important in High Tech?

In the high tech industry, whether it's server or storage or network, it's important to build a prototype to validate a theory.

Why?
"To STOP waving hands".

Some times, experienced senior people(including me) in the industry, get carried away by not focusing on to build a simple demo first to prove the theory.

IMO, "TPC"(Technology-Product-Customer) model has great probability for success.
First create Technology - Innovation, it needs domain expertise.
Second build Product based on your Technology - Execution
Finally sell your product to your Customers - Success!, if your product makes $.

So, a prototype not just validates T & P and also can get a great feedback from the potential customers! In fact, it can get you a binary answer- worth or not to pursue an idea!