It might also be tied to the fact that FFG isn't exactly a huge company, so resources are likely limited. It is possible IMO that somebody in a leadership position did the math and that RPG design man-hours would produce more revenue if invested into more material for the Star Wars RPG.
All of the above is speculation OFC, but it didn't exactly seem to me that FFG was flooding the market with new 40k RPG material before they lost the license, so it's possible they had given it up already in practice.
While this is certainly possible, it seems more likely that FFG saw the writing on the wall and didn't release anything new because they knew they couldn't recover their investment! Sad though; if these forums are any indicator, Rogue Trader was one of their more popular lines. I would have liked to have seen it updated!