In a way, you can't really fault them for staying with a certain theme or character. It's a lot of oiled finishes for the mid line stuff, nicer transparent warm colours for the higher end stuff. SR500 oiled, SR700 transparent amber/charcoal. My RGT220H oiled finish, my RGT320Q regal brown burst. RG321 oiled finished etc...
besides lots of manufactures have themes and characters in colours. Fender has a bunch of pastel colours with a handful of bursts, gibson has a wider variety of bursts with some worn ones thrown in. Ibanez just seemed to picked what they picked to define their finishes.
and before people go calling me wrong, i know that fenders and gibsons and ibanez and every other brand under the sun also offers lots of colours not related to their general style, but if you look at what they are known for, it's hard to argue that they all have trends.