I wonder, however: if having an Adele hit song persuades people to watch a Bond film (which they would usually not do) - does that mean they did not like SKYFALL and therefore did not want to watch SPECTRE?
IMO, having an Adele hit song or any hit song at all, cannot be the deciding factor for someone to watch a Bond film. Or any film. (Hey, I love the song, I have to watch the movie?)
Additional publicity? Yep, definitely. But in 2012, Bond was everywhere.
Also, quite frankly, there were many people who do not like Adele or the song.
In the end, SKYFALL was received very well by the audience and the critics, and it hit theatres at a perfect time. Kind of like perfect timing worked in favor of THUNDERBALL or THE SPY WHO LOVED ME.
SPECTRE did not have that advantage. Even if it had been a fantastic film I suspect it would always have been perceived by the non-fans as "the follow-up to SKYFALL".
Maybe it´s good to have that out of the way now.