Files should be uploaded to per year/month directories by default in expression engine

There are no year/month directories in ExpressionEngine. Although you can certainly use such URLs, they are generated on the fly.

If file dates are important it’s a good idea to add dates to either the file name, Title or description. That way they will be findable when you do a file search in the control panel.

Having files uploaded by default organized in folders as proposed, sounds terrible. I can think of far more use cases NOT to do that than TO do that.