I'm not sure Newcastle fans demand success or trophies or think they're bigger than they are, to be honest. They've not won a trophy for longer than we went without one. I think what they do expect is to feel a connection to the club that mirrors the connection the stadium has with the city. What football fans thrive on is hope and ambition, knowing that people who run the club have its best interests at heart. Allowing a manager like Benitez to leave so meekly so that Ashley can continue lining his pockets without spending any money is the opposite of what a club in their position should be doing. Their squad has been Championship quality ever since they came back up but every year Benitez has managed to keep them afloat through incredibly conservative tactics and a strong team spirit. I'm not sure a new manager, especially not Ranieri, would be able to repeat that success.
I think what makes quite a lot of Newcastle fans feel particularly aggrieved, however, is the fact that they were a good quality side before Ashley took the reigns. He took over in May 2007. In the twelve seasons before that, Newcastle's average league position was 8th and they consistently reached the latter stages of the FA Cup (finalists twice), occasionally qualified for the Champions League, and regularly competed in the Europa League. In the twelve seasons since Ashley's takeover, their average league position has been 14th (with two relegations), they've never made it past the FA Cup fourth round, and have only qualified for the Europa League once. For a club with a regular average attendance of 50,000+ I think they can reasonably expect to finish in the top half, have a good cup run every year, and flirt with European football every other season.
To know that it's not just unlikely to happen, but basically impossible because of restrictions deliberately enforced by an owner who couldn't give two shits about the entertainment value of the type of football played by the team he owns, so long as he makes a personal fortune - it must be soul-destroying. I remember when our attendances plummeted under Pearce because of how bad the football was under him, but at least we knew him and Wardle were trying their hardest. Newcastle have the potential to be as good as Everton, Leicester, Wolves, it's all there, but the environment Ashley has created sees them flirting with relegation until about the final two or three weeks of the season. Not only that, but the club is so poisonous under him now that they'll never get the players or the managing team they need because who in their right mind would go there now?