True, however the 6 year gap was a period where producers weren't likely sure they wanted to make a sequel to LBT, or were dealing with that concept in some way or another. It may have taken half of that time before they even considered an LBT sequel, let alone playing with ideas and selecting one. The gap was 6 years because I suspect most of that time was LBT stagnating until somebody came up with the crazy ideal to make a sequel.
At this point, the only possibility is that the opposite is happening: That they're going to, at some point, start debating about whether to continue making sequels. As far as I can tell, this debate has been decided on at that point when the office was shut down.
It's true, it could re-open, Negative profits and a shutdown certainly aren't good signs though. The only thing that could revive it now, as far as I can tell, is a serious fan with a lot of money and crazy enough to battle the negative image the series has had for years now with the general public (as sales numbers prove).