As far as anyone knew, HasTak had no intention of making an upgrade trailer for Ultra Magnus. History demonstrates that HasTak love to repaint Optimus Primes in white and sell them as Ultra Magnus but they never get trailer-armours. As a result fans made one for Classics Ultra Magnus. Because, as far as is known, HasTak had no intention of making one themselves, they haven't lost any potential income from the fan item as a result.

A KO reissue on the other hand threatens to reduce demand for a legit version of that product, and thus in turn effects HasTak's business making decision. The Sunstreaker mould is only rumoured to have been lost and HasTak has neither confirmed nor denied this, so for argument's sake let's assume that they still have the mould. Now because there's a KO Sunstreaker coming out, Takara would now ask themselves why they would bother making a legit reissue as the demand for a G1 Sunstreaker may be effected by the KO. Many collectors may be satisfied to purchase a KO and not bother buying the legit version, which Takara may in turn see as meaning that it would be too risky for them to reissue Sunstreaker. The decision for them is compounded further if the G1 Sunstreaker mould has (as rumoured) indeed been damaged or lost/destroyed as it means that TakaraTOMY would have to spend a lot more money with R&D in terms of restoring the mould. We know that in 2000 when Takara reissued Convoy for the first time that they took what was left of the G2 Optimus Prime mould (which was the whole toy but they'd the arms were destroyed or lost) and spent a lot of money restoring the arms for that mould. Takara have stated that this was a _very_ expensive venture for them, but they calculated that with a character like Optimus Prime, the demand could justify the expense. And we've seen HasTak milk this reissue mould for all it's worth; I cannot think of any other Transformer toy that has been reissued more times than the 1984 Optimus Prime mould! AFAIK Takara(TOMY) have not gone to that much trouble and expense for any other lost or damaged mould for a reissue.