Perhaps the writers are the only ones doing stuff so they decided to close down the office and stop paying the animators and crap for sitting around. They'll re-open the office once the writers come up with something.
Depending on how Universal Studios hire their writers for LBT, that might actually be the case. While I think TV series generally have their wriyters in a semi-permanent state of employment, hiring writers for films tends to be a more one-off thing. Obviously, something like LBT, which has put out many films at a fairly constant rate for a while now, could be anywhere between the two.
If we assume for the sake of argument that the LBT sequels work like most films, then it wouldn't generally be the writers who come up with the basic idea. It would more likely be a producer or a director, for instance. The writers would simply work out the specifics of the plot and write the script (which would probably be changed to some extent later).
In short, if they're just waiting on ideas, it would probably be producers (or possibly a director like Charles Grovesnor) who they're waiting on. Producers could easily be working on other projects in the meantime, probably more easily than animators, who would form a much larger portion of the office's employees.
Writers, in the meantime, just get screwed, as tends to happen to writers.
Hopefully that made some level of sense.
