have they not:
1. announced three films in three consecutive weeks (original trilogy, around may the 4th thru the end of may)
2. waited a week or two, then announced three more in three consecutive weeks (prequel trilogy),
3. waited another week or two (since the revenge of the sith pre-order went live), then teased TFA earlier today so that'll probably be up for pre-order this thursday
who knows if they'll do 5 consecutive weeks from here on out and include rogue one and solo between sequel movies, or just announce the sequel trilogy over the next 3 weeks, but that still seems like a consistent pattern.
I make the pre-order schedule:
A new hope-7th May
Empire -21st May
Return of the Jedi- 28th May
Phantom Menace- 11th June
Attack of the Clones- 25th June
Revenge of the Sith - 9th July
The Force Awakens- 16th July
So release, 2 weeks, release, 1 week, release,
2 week wait between trilogies
release, 2 weeks, release, 2 weeks, release
Then no wait between trilogies with release this Thursday for TFA.
That makes no sense to me, but monthly would have made perfect sense. I do hope it's weekly for the next 5.