There are two sides to BRexit - the economic and the political. The reason why businesses do not have a vote is: society is comprised of people and people are, supposedly via the ‘social contract’, represented by government. Business interests are of relevance but the economic is secondary to the political in terms of the interest’s of the people.
Just because the economy and business would do better that would not, for example, justify having a despotic totalitarian government. People come first.
Businesses have to fit-in with the political landscape that is generally best for people. That does not mean businesses needs are of no relevance, clearly society needs a thriving economy so it is greatly a balance.
Where there is a fundamental people rule. Exiting the EU is a political fundamental. If the EU was just a common market as originally described we would still be a willing partner I am sure. But it is not. The EU has become a political construct and it is that which has been firmly rejected by a majority of British people in a democratic referendum.
Live with this change. We will adapt. Stop whining about economic downsides because that is not what is important. Leave understands the political need for independence.