Yes, this is true. Before Beast Wars there was no such thing as established size classes/price points. Beast Wars introduced this concept and it's stuck ever since.
BW didn't had Supreme or Leader Class. BW had Basic (Scout/Commander), Deluxe (Deluxe), Mega (Voyager) and Ultra (Ultra). An example of more recent Ultra Class TFs would be Universe Powerglide, Onslaught, Silverbolt etc. BW also had Super Class, which was Optimal Optimus.
Supreme Class was introduced in Beast Machines, the first beingoverpriced-piece-of-crap^Supreme Cheetor. Examples of a more recent Supreme Class toy is Animated Roll-Out Optimus Prime.