I don’t know why “senior executives” need data access to financial databases (point of sales, not sales figures).
They don’t “need” to, they want to because of the Executive Power trip or rush from having CONTROL!
It is not that they necessarily have access, they are just on the network and have a route to the server IP. You can set up your network topology differently if you want, but it has nothing to do with what OS the executives have.
When I was working, I worked at a major bank. They set up a network for executives and vendors that was completely separate from the main network. They had their own set of IP addresses and were completely isolated from the main processing network of the bank.