The OP is asking one question, but most buyers that already HAVE a reasonably recent arranger are asking themselves another...

Is the (at least) two grand or so I am going to have to pony up for the difference between selling my OLD Tyros in a very depressed market and buying a new one going to be worth it for the tiny handful of new voices, a few new styles, and precious little else?

In today's economy, I doubt many will answer 'yes'.

Tonewheel is very on point, IMO. And, in a dwindling economy, diminishing returns becomes a MUCH larger factor. The cost of upgrading stays high, while what one already has is ALREADY so good, it is usually considerably more than the average user (and some well above!) really honestly needs. So many Americans, Canadians and EU citizens have lost so much equity in their homes, honestly... do you think that several thousand for a few more voices and styles is going to be as attractive as it was when the bubble was booming and cash was flowing like wine?

Yamaha, and I believe the entire arranger industry has only one chance. You don't go chasing the customers you already HAVE (that's how the home organ industry destroyed itself). You find NEW ones. And where are these new customers? KIDS! Young players...

And the arranger is NEVER going to appeal to them without a major overhaul in capabilities and sound to reflect what is current TO THEM. And sad to say, it seems like the arranger industry is bending over backwards to make sure NOTHING contemporary gets put in an arranger. I have a nasty feeling they are just positioning themselves to go fight for the dwindling, aging current market. You can pretend that the home organ industry is healthy, but compare sales figures from the mid-70's to now. A pittance.

That's where we are heading, mark my words.