Only thing I can think of is because it didn't sell well enough for their bean counters to okay continuing it. It is a fabulous model; I have two of them. A marvelous flier, and the kit quality was second to none. The canopy/hatch is a beautiful work of art.
But it was priced a bit steeply, compared to the myriad lesser-priced (and lesser quality) similar offerings from other hobby distributors.
As is usually the case, the cheapskates win yet again. Far too many of our fellow "modelers" are more concerned with price than quality; so the sellers give us exactly what we are willing to pay for. Sig's new crop of ARFs is a prime example of this. Seagull models are okay… but not even close to the standards of older Sig offerings. That is only my opinion, true; but I've had both. YMMV...
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Too bad… this was a most excellent airplane, of exceedingly high quality and fit/finish.