To add to other replies. For a long time, Postgres did not run on Windows which was and is the dominant OS. This was the days before affordable VPS were availab

To add to other replies. For a long time, Postgres did not run on Windows which was and is the dominant OS. This was the days before affordable VPS were available for you to spin up a server. You developed your site on your laptop and FTP's it to hosting provider. Edit: Added more context