There were 2 years between PSR740 and PSR2000. 2 years between the PSR2000 and PSR3000. The PSR2100 came inbetween, but it was essentially the same exact keyboard as the PSR2000. So I believe that we can expect the successor to the PSR3000 to come out next summer. I would be shocked if Yamaha waited 3 full years.
The PSR3000 came out 6-8 months after the Tyros and had a lot of the same features. Hopefully, the next midlevel arranger will come out some time next year and will have many of the same voices, styles, and other features as the Tyros2.
Beakybird