It definitely would be awesome to have the big MIB guns, the Pulsar Blaster from MIB 2 (the one with the two barrels) was my favorite out of the big guns. I don't feel sorry for these companies either, the way I see it is that these companies just haven't executed these props well enough which is why they're not selling ergo why the demand isn't as high as it should be.
Factory Entertainment, despite being the frontrunner for the MIB props, didn't do as great of a job as they could've. The J2, Neuralyzer, and Noisy Cricket props were the most accurate with how they looked, but how they operated is a whole other story. Granted I've only ever seen the unboxing videos they did (which most of the videos consisted of pointing out how well packaged the props were) so I don't actually own any of the props, however the videos definitely show what some of the reviews I've read have also said. The J2's lights and sounds were completely off, the red light for the laser sight on top of the gun was made to be more like a flashlight than a laser sight in the prop, in the film the light does not look like that. All the sounds are completely inaccurate as well for how the gun actually sounded in the film. The Noisy Cricket also sounds nothing like how it sounds in the film. As for the Neuralyzer, this is a huge letdown. For one, that constant ringing sound is a lot less present in the film and in the prop it actually sounds more like the Noisy Cricket than the Neuralyzer. And for two, the flash for the prop isn't even that bright. And also many of the reviews I've read have stated that the Neuralyzer is very fragile and breaks easily.
The point is that the demand isn't as high as it should be because these companies have done a very poor job of replicating the props. There's no way I'm gonna spend $400 on a prop that isn't as accurate as possible, especially for the Neuralyzer which I really wanna get my hands on one. I mean we can't even get a decent MIB toy gun or Neuralyzer let alone the prop versions (I'd settle for a toy version if it was really good, but there isn't even any decent toy versions out there, the most accurate toy Neuralyzer is the costume one from Disguise that doesn't have any lights or sounds and you have to manually open it and close it). When SAT came in I had hope considering they actually made the props for MIB 3, but they just completely disappeared out of a nowhere. The MIB 3 guns are awesome, but my main concern is the MIB 3 Neuralyzer. Considering the Neuralyzer from MIB 3 has a much simpler design than it's predecessors it shouldn't be that hard to make, and it would be a lot cheaper too than the MIB 1 & 2 Neuralyzers. SAT promised this and many other things but never delivered, and it would've been a very simple task to at least give us the MIB 3 Neuralyzer.
If a company can actually make decent MIB props then the demand for them will increase.