If that were the case, United would be broke, with no quality manager even considering wanting to join, and academy in decay.
Glazers consistently are using United as a cash cow, instead of running the club properly by paying down the debt as fast as possible, hiring a DoF and re-structuring the academy. It is them with Sir Bobby who are holding back firing managers because "they don't want to become a sacking club". It's them listening to Sir Bobby who said they shouldn't sign Mourinho because he doesn't fit in with United's ideals and way of doing things (hence that letter than Mou wrote explicitly said he is willing to keep to the tradition of United). Sir Bobby, SAF and the Glazers need to remember, that those old glory days of 26 years or even 12 years of management are over. Get with the times.
Woodward on the other hand is mediocre at signings, but he's one hell of a marketing and financial beast, managing to find new revenue streams on what feels like a quarterly basis. The Glazers would not achieve the financial income that United has without Ed.