While there is nothing you can do to bring back the legacy Excel menu and toolbars, you can make the ribbon behave a bit more like a old style menu. Press Ctrl+F1 or right-click the ribbon and choose Minimize the Ribbon. Excel hides the ribbon, which looks similar to the legacy Excel menu.

After the ribbon is hidden, you have more room to work with your document. You also can click any ribbon tab name at any time to open the ribbon temporarily. After clicking the menu item, Excel returns the ribbon back to the minimized view.