Newly created jobs need to be set for failure notifications automatically
I'd suggest checking out this post from Greg Larsen - Automating SQL Server Agent Notification.  You could manually create a SQL Agent job that runs periodically and searches for enabled jobs that don't have any notifications defined.  

Here's an example of a dynamic SQL query you could put in a SQL Agent job to find SQL agent jobs without notifications and dynamically update them to have notifications.  Make sure you uncomment the EXEC when you put it in a SQL Agent job.  You will also have to modify the variable @Operator to specify the operator you want notified.

USE [msdb]
GO

SET NOCOUNT ON

DECLARE @ExecStmt VARCHAR(4000)
DECLARE @Operator VARCHAR(50) = 'DBA' -- place your operator name here

SELECT @ExecStmt = STUFF((
            SELECT ';' + 'EXEC sp_update_job @job_name = ''' + j.[name] + ''', @notify_email_operator_name = ''' + @Operator + ''', @notify_level_email = 2' -- 1=On Success, 2=On Faulure,3=always
            FROM dbo.sysjobs j
            WHERE j.enabled = 1
                AND j.notify_level_email &lt;&gt; 1
            FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)'),1,1,'')
PRINT @ExecStmt
--exec (@ExecStmt) 
GO