Because collectors spend lots of time and money accumulating this stuff and it's not only a slap in the face to them, but also completely undermines the pizzaz and value of the collectibles themselves. See HT MK 47, Sideshow Grievous, etc etc for reference. Reissues diminish the fun of collecting, the collectibles aren't as special anymore.
Nobody is entitled to buy whatever they want whenever they want at retail. The run sells through and that should be it. After that go find it third party if you want it badly enough. I want a '63 split window Corvette but Chevy won't make me one and nobody out there will sell me one for the $4k it cost in 1963. So boo hoo for me, if I want one I have to work my @ss off to pay for it.
I have to respectfully disagree here. Personally, I do not mind if something is reissued and how it affects the value of my own toy. Comparing this to a car is not the fairest comparison. Maybe more like a book... which gets more printings.
Reissue in this case has nothing to do with entitlement. Reissue is a manufacturer choice, wanting to make more money on its items. And no one is entitled to a limited run unless the run was specifically designated and promoted as such.
I'm of the mind, as long as I can get one, I am happy. The more the merrier.