Its a good speculation, but its just that ... a speculation.

True. And while I got my info from Larian at the weekend, it's possible that all the confusion has changed plans, so I'll stop assuming I any longer have any sort of inside scoop. For all we know Larian have been desperately scrambling to see if they can release on 31 July after all and that's the cause of the delay in the update

Wait and see is good advice.
My main concern is why 3 days would make a huge difference, especially after bumping it froward so much and since one would expect press to already have been playing the game prior to the 3 day head start. Don't mean to be negative, but if three days is so important is suggests that the bump forward was indeed a somewhat desperate attempt to avoid Starfield without falling into the huge spread of game releases coming after, meaning they'd basically have to release in January of next year to avoid the same problem with other games.
It almost sounds like they're scrambling to put finishing touches to hit that new sped up timetable and believe even 3 days would help.
Of course, I do still completely agree that wait and see is the best approach, but imo people are worrying about the wrong thing, it's the fact that this is even a contention that's baffling. Why is such a small amount of time important at all after a 30 day bump?