The reality is SW, like Bond, is an old franchise . It still makes money. and is beloved ,but it is an old franchise. That's demonstrated by the reality that most of the SW fan civil war is between middle aged and thirty somethings on both sides who were kids in the 70s through the 90s.
I think if there's any decline in SW it has less to do with a polarized fanbase ,and more to do with the fact that SW is something that's been passed down over 40 years to the children of today as opposed to the MCU in which was made for the children and teens of today.
The MCU is very much this generation's SW saga. That's not to say SW isn't popular , and won't make a fortune, but it means that it may not be considered the be all and end all to children who literally grew up with the MCU films .
I'm not going to argue about the MCU being the hottest property in movies worldwide, it is, clearly.
However the force awakened was the highest grossing movie in the US ever and still is, it. That was in 2015, so that didn't stop this generation turning out in record numbers. What has changed since then? Obviously the 10 year break helped with that particular box office, but if the subsequent movies were any good then episode 9 should gross between TFA and TLJ right? If we think it is going to follow the OT BO pattern. If it doesn't and it earns less than TLJ, then that is proof that Disney has mismanaged the SW franchise, and what it has done with this trilogy has not resonated with the fanbase. If it grosses more than TLJ, then maybe everything is fine after all.
The google trends and general lack of enthusiasm on social media and youtube is one indicator, but we won't know the reality of the state of play until December, everything else is opinion and guesswork.
However this being a Box Office thread, my prediction is $1-1.2 Billion, that is what I voted. It is very hard for me to imagine it doesn't at least gross a billion.