There's probably a number of issues. The vehicles were based on actual vehicles, so to produce them now may require licensing from the car companies. (I don't believe that was required in the 80's) The vehicles were fairly complex, so it is likely cost prohibitive or at least more so than with vintage figures. Finally, the property does not have the kind of fan base that other properties that have come back have. So a simple reissue would have a fairly limited market.

I would LOVE to see some MASK vehicles come back. I think that is what was tried with Mattel's car line a few years back. They didn't do well with kids. Vehicles simply don't do really well anymore. That being said, I look for original MASK stuff on evilbay from time to time. Still some good deals to be had if you are patient.

M.A.S.K. was semi-re-imagined in the 90's under the toyline and toon, VOR-TECH. It featured vehicles that changed into other vehicles or armored battle stations. In fact, it used re-tools of some M.A.S.K. vehicles, like Gator, Bullet, and Firefly. All in all, it was pretty neat little line, but it never really found an audience. The toyline lasted a year, and the toon ended on a cliffhanger. Alas.

More here:

http://www.albertpenello.com/mask/vortech.html

http://www.albertpenello.com/mask/