The thing with Scourge is that...he is his universe's answer to Nemesis Prime. Had they gone ahead with that name in 2001 I doubt anyone would have batted an eye.
Thing is they didn't- he was Scourge. And the fact that he actually got character further differentiated him from his other "black and teal evil Optimus clones" peers. It's one of the the little inconsistencies in this franchise that are, frankly, fun. Nothing was planned out in any grand vision (which makes attempts like the Binder really hilarious). It was all done by the seat of their pants and that's perfectly ok. Leads to crazy stuff that doesn't make sense.
I agree. Had the name "Nemesis Prime" been conceived and Trademarked by Hasbro back when the RiD 2001 series was being dubbed, Scourge absolutely would have had that name.
Before he was "Scourge", he was "Black Convoy". Not "Black Fire Convoy", but "Black Convoy", the equivalent of "Evil Black Normal Optimus Prime", rather than "Evil Black Car Robots Fire-truck guy who looks like Normal Optimus Prime". It took a while, but the names "Black Convoy" and "Nemesis Prime" were always supposed to be as synonymous with each other as just "Convoy" and "Optimus Prime".
The whole mess with the names that there was at the beginning was because of the name "Nemesis Prime" having not yet come about and the Decepticon Leader had to be named
something. Hasbro picked a preexisting Trademark that they still had and just slapped it onto the guy, never expecting his popularity to soar the way it did and not expecting that fans would care so much about this particular Black Convoy/Nemesis Prime named "Scourge" more than most other Black Convoys/Nemesis Primes that would come later (all thanks to his being a major character in a TV series and having a unique deco that most future Nemesis Primes/Black Convoys would never utilize, thereby making the Car Robots/RiD version all the more special).
Heh, at the time when the first use of the name "Nemesis Prime" came about during Armada, Takara seemingly tried to streamline the "Scourge" name to refer to this character archetype by naming their versions of Armada and Energon Nemesis Prime "Scourge" and "Grand Scourge", respectively (as a mirror to Armada and Energon Optimus Prime being named "Convoy" and "Grand Convoy" in Japan, respectively). But evidently, that never stuck since not long after came the Alternators and Binaltech lines creating the first definitive black-and-teal evil clone of G1 Optimus Prime himself, named "Nemesis Prime" and "Black Convoy" in each respective line.
It was here that the two names were finally brought together as one consistency, and have continued to remain synonymous with each other ever since, leaving the old "Scourge" name in the dust, never to be used again for the Black Convoy/Nemesis Prime archetype by Hasbro or Takara in any
mainstream capacity, only ever used again by the likes of Fun Publications (for TFSS Scourge) and e-HOBBY (for UW Grand Scourge) in uber-nerdy, collector-oriented releases of those specific versions from the English RiD and Japanese Energon series, aimed primarily at longtime fans who are familiar with those two, rather than the mainstream market.
Up until Rise of the Beasts, the only legacy the name "Scourge" had for being the name of a Decepticon Leader was in the Cybertron series using that as the English of another Decepticon Convoy, Flame Convoy. It is my belief that he was given the name "Scourge" primarily because of that name having already been used before as the English name of the first Decepticon Convoy, Car Robots Black Convoy/RiD 2001 Scourge. Had the name "Nemesis Prime" been used instead, who knows
what Flame Convoy's English name would have been. "Predaking", perhaps? His colors were very G1-Predacon-esque, after all. Though, who knows if Hasbro had the Trademark on that name at the time. Or even "Sky Lynx", which was a preliminary name for Flame Convoy.