You have invented a better mousetrap and now you have a group of people willing to invest in your startup business. The first thing they are going to do is calculate how much it will cost to sell their current investments for the cash to invest in yours. A 15% tax rate on capital gains may be doable. However, 30% or 40% may wipe out any advantage in the new business.
When capital gains were paid the standard tax rate money stayed in the investments in old inefficient companies. When the rates were lowered, small business flourished. Lowering capital gains rate caused companies like Microsoft, Apple and Amazon to grow into economic giants. The question is, should you pay excessive taxes to loan your money to help other people?