They should've release T-80U/T-80UD first

Hi; Well actually, they announced the T-84 & the T-84M in there 2017/18 catalog, along with the Black Eagle !! CHEERS; MIKE.

somebody start producing modern parade figures in styrene for thee beasts

That doesn't seem to be the way they do these things - the pattern seems to be "do the more obscure version first, release the common one later". My theory for "do the obscure stuff first" is that "T-80 fatigue" (in this case) will take longer to set in if they leave the most desired versions until last. That is, if they do a T-84, and an Oplot-M, hardcore T-80 fans will buy those, and then still go on to buy the T-80U and T-80UD when those come out because they're major versions and, no matter how many T-80s you have, if you want a "representative" T-80 lineup, you need them. Whereas if they release the T-80U and T-80UD first, by the time they release the T-84 some people will be "welllll, I've now bought a T-80B, T-80BV, T-80U and T-80UD, that's all of the major versions bought, I should stop". Doesn't fully explain it though - after all, wasn't the T-80BVD released after Trumpeter's B and BV?

Dragon released a T80 version years ago. I understand that it wasn't well-executed. Or maybe the design team was well-executed after its less-than-stellar release...

The Dragon t-80 kits were offered over a quarter century ago, just before detailed information on Soviet military equipment became available when the Cold War ended (timing is everything). Of course nobody on the design team was "well-executed," as Hong Kong was still a British Crown Colony, and it just wouldn't have been the sporting thing to do, old chap. However, should anyone feel the atavistic urge to struggle with bad old kits from the dark ages of modeling, the Dragon T-80's are currently available from Zvezda (and occasionally, Revell/Germany).

Still waiting for T-80U from this guys

Same procedure as many other industries/businesses. Release the obscure or premium versions first (scale models of tanks or 1:1 scale cars, doesn't matter). In this way one can sell the obscure or expensive versions to those who really want to have one or have got the money for the premium car. Then the market "onion" is gradually harvested layer by layer until it is time to release the most common or least expensive (budget) version. / Robin