I too was hoping to see a PX-5S replacement. But I also had my eyes set on Yamaha, for a MOXF replacement, and that didn't happen either. Instead, Yamaha launched 2 new PSRs.
I think it's all about sales. I'm sure the PX-5S replacement is coming soon, just like the MOXF replacement. But while there are still enough buyers for their current boards, both Casio and Yamaha they're taking their time. Anyone who can no longer restrain their GAS is going to get a current board (some will choose another brand, but some will stick to what they've been eyeing). Then, when the successors are out, many of those people are going to upgrade to the new boards - that means 2 purchases in a relatively short time. I'm not a sales expert and I have no idea what the actual numbers are, of course. But my guess is, if they haven't put out the replacements yet and they haven't discontinuted their current boards either, there's probably a careful calculation behind that.
