It's all about finding the balance between signing players to improve you and not doing a Manchester United and throwing cash at everyone and anyone.
That being said, if the thing about Poch not having control of transfers is true then you really need to scrap your current setup. We had that issue when Brendan was in charge and we ended up getting a load of crap players he didn't really know what to do with.
I'd say there 3 ways of doing it
The City & Liverpool way - The manager identifies the players he needs and the board goes out and signs them
The United way - The CEO with no footballing knowledge or business acumen identifies the players, pays over the odds and then expects his managers to get results
The Spurs way - The CEO does very little and expects the "head coach" to continue to deliver results on the pitch
Even if you take City out of the equation because they are clearly on a different level to everyone else financially, it shouldn't come as a major surprise to see which method leads to trophies and which ones don't