Industry and idiotic Twitter boxoffice pundits. They don't understand ground realities and are far away from pulse of the audience. Most of these folks make their predictions on the basis of emotions and their fav actor /actress. Never think logically.
In this movie's case, I would say many things have gone wrong.
1. Salman is overexposed. Has done a lot of flop/bad films of late
2. Flop songs
3. Diwali period is tricky for movies. Some do well and some underperform
4. Cricket World Cup
5. Lame marketing
6. The story of the movie was unacceptable to the general Indian public
Comparisons to Pathan, Gadar 2 and Jawan were stupid. It was never going to do those numbers, as the buzz was nowhere close to those films. Best case scenario was 500 cr if all was perfect. That was not to be.
Yrf will obviously be nervous going forward with their spy universe. They will probably just hope for the best with war 2, but keep expectations in check. They need to work on their marketing and release strategy though. Also, ensure not to have stupid unrealistic storylines of Indian agents teaming up with enemy nation agents to save enemy nation PM from an ex agent of enemy nation gone bad. Jesus.
If the reaction to post credit scene is any indication, war 2 will do just fine. Maybe not Pathan, Jawan or Gadar 2 numbers, but still very good numbers. Having Jr. NtR will enhance the numbers in south.