Um, no. From Forbes:
"We gauged the Best Countries for Business by rating nations on 15 different factors, including property rights, innovation, taxes, technology, corruption, freedom (personal, trade and monetary), red tape and investor protection. Other metrics included were workforce, infrastructure, market size, quality of life and risk. Each category was equally weighted."
Which, if any, of these metrics are Brexiteers destroying? If anything, the opposite is correct, each of those will be enhanced!