It's not unreasonable to expect a manager to show some financial acumen. Maybe the MD should know better but so should the manager. You can't just keep asking for players and expect not to run into trouble. Sometimes it's up to the manager to manage what get has better and stop trying to recruit your way out and stop asking, and not just the MD to be the bad guy to say no.
Look at Man U. Mourinho doing all the moaning about not recruiting enough. Spent 89m on Pogba, 50m on Fred on top of what he already had. Apparently Woodward vetoed swapping Martial for Alderweireld. Why wouldn't he? Swap a soon to be 30 year old with no resale value for a 22 year old with a great deal. Why should Woodward be the bad guy? Why doesn't Mourinho do more to get the squad in check?
The manager knows the size of the club and what it can sustain. Bringing players in on huge wages is bound to cripple many a club, especially if you're not doing your bit to get them out too. A lot of Redknapp's victims has seen him recruit en masse as if there wasn't a player there already worth using.
"I won't pull the owners pants down" Wilder often says, showing he at least has that understanding.
To suggest Redknapp was blameless and had no concept of balancing the books is bizarre given his level of experience.
Then again, maybe he just left that to Rosie.