theres a simple answer for that my friend that everyone has overlooked.
It makes good cinematics.
plain and simple. The time that passes int eh trailer and Indeed MANY of the shots that look like e.g the rebels running to ambush the AT-ST, they were actually filmed about 1.5 hours apart from ach other.
It's teh magic Of editing y friend.
time passes in a way that may seem coherant but in reality the length of time we spent filming was probably 3 hours or more tbh.
A good example of this "seemingly co-herant time, yet time is passing faster than you realise" would be Revenge of the sith.
Padme goes from discovering she's pregnant, to giving birth to Twins, in approximatly 120 mins or something.
With no visable "X months later " signs in sight, the movie plays out like a coherant passage of time, which is obviously not teh case due to her lightening fast pregnancy 