> Here is my Question: Why did we stop with “single market” efforts? Why is there no effort to unify legal entity in Europe?
I'm not sure the author understands what he's asking for.
While having California residency, you can start a Delaware company, open offices in California, pay taxes to the State of California. If the State of California sues your company for unpaid taxes, which court do you end up in? California. If the State of California sues your company for civil rights violations, which court do you end up in? California. The US doesn't have some magical system where just because you register in another state, you can resolve all legal disputes in that state, therefore you're not beholden to the laws and governments of the state you operate in, or that Delaware is legally bound to enforce the laws of the other states and localities you operate in. Indeed you are beholden to said laws and localities. And indeed, complying with 50 different states and all their localities can be so damn complicated that there are entire products built to help you figure out how much sales tax to charge when crossing state lines, as well as how to pay it correctly; not to mention how to offer health insurance to remote employees, since every state has its own insurers.
At the end of the day, sure an "EU Inc", as the author puts it, may help make it easier to close deals. But it does not reduce the operational complication of operating across different localities. The rights of different localities to set their own laws and regulations for those who operate within their jurisdictions is unavoidable. You could have a single Brussels sovereign and a single English legal contract language and this would still be true, because it's already true in the US.
The EU has a "single market", not a "single marketplace". The market is the customers, not the companies, not the banks, not the courts.