I have a fundamental disagreement with the idea that many of the styles are out of date and geared to older players. I think it has nothing to do with age, and a lot more to do with what kind of music lends itself to being 'played' on a keyboard. I don't think it matters what age you are, or when the song was written, there is a type of music that lends itself to keyboard playing, and some that don't. Much of the music I have played all of my life comes from an era before my time, like Kern and Gershwin, and much of it is relatively recent, maybe Adele, but I play it all because it is playable. It has a clear and memorable melody and harmony. That is what works in live playing on a keyboard.
A lot of commercial modern music is great, but its more about musical production, atmosphere and driving beat, creating a party, dance environment that many love. But you can't really sit down and play it. And the majority of people buy arrangers because they want to play.
Of course there are many people interested in music production, and they are constantly telling us that the arrangers need to be updated to emulate what is done on workstations. But they are a minority. There is also a number of players who do party gigs and feel obliged to throw in some of this kind of music, but again they are a relative few.
A perfect example of this is my grandson who has been professionally producing EDM for many years. But when he sits down to play a musical instrument in his room, he plays exactly the same kind of music that I would play. He has told me many times that EDM is not made to be played, it is primarily there to create a party atmosphere, with a driving beat, and there is a clear formula that works. He believes that most people don't really even hear it, or could hum it afterwards.
I believe that as we age, many people who played earlier, or never played, develop a strong urge to be able to play. The arranger has been the perfect vehicle for that. The idea that as the 'young' set age they will demand arrangers made for 'their' kind of music is myth. They will sit down to play exactly the kind of music we all play - because that is what is playable, satisfying and entertaining. I am not of course against constant improvement of the style technology, the styles themselves, or a wider range of additional styles. But I am still playing 'All the things you are' written long before I was born, and I bet they will be playing 'Yesterday', 'The Long and Winding road' and 'Moon River', long after I am gone.
Mike