The Broncos would be absolutely falling over themselves to get to him right now. This is a club listed on the stock exchange, has one team in a city of over 2 million people, a state of the art 52000 seat home ground with an average crowd in excess of 30K and money to burn from very, very wealthy supporters. They're desperate to get back on track having only had maybe two decent seasons since Bennett left. They are going to want him back ASAP and will probably pay whatever it takes to do so.
That said, maybe the legend grows if a decent ownership model is put together and he stays to steady the ship, possibly (and very likely) for less money than the Broncos are now throwing at him.
You cannot blame the bloke for leaving Newcastle now, that's for sure and certain.