The BB's have explicitly stated that at present the cost of high level staff does not equal their benefit except for the mightiest of teams. However, overpaying gives us a false sense of security - "it's not my fault, I have a level 6 PR..."
You can either by with your heart or with your brain.
I chose the former and my level 6 PR guy was bringing in over15% more scratch from merch for a while. The last two economic updates have seen this $$$ drop by over 12k, even though I am doing well in my league.
Once I scored a basket that still makes me laugh.