It’s the usual chicken and egg situation, Arranger manufactures will not incorporate the latest styles unless there is a demand, youngsters won’t buy Arrangers unless they have the latest styles.
There is a possible kick start, (If manufactures don’t want to spend money immediately) and that is in their sales blurb and demonstrations, point out how it is relatively easy to convert a Midi file into a Style (Virtually all upper range keyboards have this feature) and use a Hip Hop, Rap etc Midi file for the demo.
This will hopefully create the demand that the manufactures look for.
Just a thought

Bill