No reason to think that ITAR comes into it. There is no evidence that >9fps is possible, and if it was/is then they are just plain incompetent. Even if it is, it may well be too noisy to be useful, and hard to fit a bigger lens.
OK they have sold a ton of E4's but will have lost out on the excessive profit margins on the higher end models.
What is slightly puzzling is why they didn't at least do some simple interim countermeasures much earlier, which they could easily have done. Obviously it takes time to develop and test the changes needed for a more robust approach, but they could have easily done some quick, low-risk changes to at least throw up some FUD. Maybe they were just too busy with FlirOne.
I would imagine there are some internal politics involved as well as technical issues, which makes it hard to know what's really going on.
I wouldn't be at all surprised if the FlirOne/Lepton stuff could be a factor in the overall strategy, e.g. maybe E4 becomes Lepton based, with a real 80x60 sensor.
Maybe they always planned to base the E4 on Lepton but had to use the 320x240 sensor as a stopgap?
Only time will tell.