I feel like Calgary fans value Bennett as though he will hit his ceiling for sure while other fan bases values him as a early 1st round pick who hasn't made the impact in the NHL you would hope for from a 21 year old top 5 pick.
You're painting Calgary fans as being solely fixated on his ceiling. There's more to it:
Bennett is a 21 year old center who hasn't played an NHL game as a 21 year old yet.
Most offers for Bennett are 26+ year old players with a year left on their deal, who don't fit our long term window or wingers, who, well, are wingers. Often, for both at the same time.
Bennett doesn't need to hit his ceiling to still be a very good center. His ceiling with his hands speed and vision is truly high-end but a few steps below would still be an upgrade on Sean Monahan. Even a Nazem Kadri type "plan B" outcome is more useful to a contender than a lot of the offers being discussed.
Bennett also essentially missed most of his Draft+1 season.
Bennett may have been ranked higher than certain others before his draft, but NHL readiness is a thing. Some players are ready to contribute sooner and put into a role to do so, others might have better projections but need physical development, coaching, experience to get there. Bennett wasn't coached well as a center in Major Junior, and that was why sending him back made no sense either, before you say he was rushed there just wasn't a good choise because last year was his first AHL eligible year and he already had a year (at LW) in the NHL under his belt. He made huge observed strides in his game last year from October to April - only people not watching him think he stagnated. Physically he is still immature, and loses balance at times and lacks strength at others. These are things that are normal for 20 year olds, and guys like Matthew Tkachuk and Leon Draisaitl who are physically mature at 19 are not normal. There's nothing stopping Bennett from filling out his frame with Zetterberg type strength.
Bennett's point totals also shouldn't be judged independant of his role. He got the worst wingers, the awful third defense pair the most often, and his quality of competition actualy wasn't far behind Monahan and many other quality scoring centers. He was put in this situation because developmentally it was better for him.
Finally, our scouting staff and development team has a history of drafting slow-burn NHLers rather than favoring NHL readiness. Backlund took 10 years to hit the 50 point mark, when he turned 21 he only had 12 NHL GP and it was still a long road to mature into the player he is now. Brodie, Giordano, Gaudreau were not instant successes either at Bennett's age. Ferland is just now hitting his stride as a top 6 forward. Baertschi and Granlund had impressive seasons last year. Jankowski was drafted with a 6 year path to the NHL described the night of his draft and yet the Flames were happy to do it. Klimchuk and Poirier have been brought along slowly. Kylington and fox were more players who obviously needed extended development time. Tkachuk and Monahan were exceptions to the Flames' draft history - our team is almost completely homegrown and it is all about exercising patience. Bennett being taken 4th overall does not mean the Flames ever saw him as a player they planned to plop onto the first line and let fly.
Will Sam Bennett hit his ceiling? It doesn't matter, he is not a finished product. He could only hit 75% of his ceiling and be a fantastic two-way top six forward. If he did his his ceiling though, Tkachuk and Bennett would be a nightmare first line for the NHL to deal with, never mind having Gaudreau, Monahan, Jankowski, and Backlund all locked up within a mostly sustainable cap structure.
