It's definitely possible - the original LotR movies succeeded at this. Fans had big lists of criticisms but despite that largely loved them.

The opportunity cost is there to prevent that, and the tastes of the fans don't always coincide with the general audience.

I don't think that is true. There is some complaining, but in general popular franchises are popular for reason. There likely were enough things that appealed already substantial audience. Just keep those in and adapt what has to be adapted for different medium.

I'm not saying make a product for only the fans. But stay honest to source or previous material.