I was only 4 in 1984, so I didn't really start choosing my own Transformers purchases until late G1. ALL of those were nobodies who had never appeared on the cartoon (I had never even heard that there were Transformers comics, so if it wasn't on the cartoon, I hadn't seen it). But as long as the toy was cool, I could make up my own backstory. Giant monster lizard warrior who had a robot motorcycle inside of him was fun even if I didn't know who Iguanus was SUPPOSED to be. Same with Countdown and his rocket base or any other late G1 toy.
For a kid these days, they don't need to know who Jhiaxus is to find it a cool looking robot. They'll fill in the details. That's where Transformers is well suited to appeal to both us "olds" who want to see obscure characters represented AND kids that just want a cool toy.
Star Wars can do this, too. Darth Revan is a cool looking badguy even if you've never played KOTOR. But yeah, random Cloud City background guy holding an ice-cream maker is gonna make a lot of adults super excited, but it isn't gonna appeal the same way to a kid.