What others have said but also keep in mind many corporate environments have been running windows dns for nearly 20 years. DNS migrations from windows take year

What others have said but also keep in mind many corporate environments have been running windows dns for nearly 20 years. DNS migrations from windows take years. So many subtle changes, delegations, forwarding etc etc. Windows DNS isn't the best but it's reliable and gets the job done. Plus, quick and easy dynamic DNS entries from windows servers or workstations using AD computer account auth