Hard Drive Interfaces

I found an interesting graph today showing the up-coming status of different interfaces for either the 2.5" and 3.5" Hard Drive formats. The 3.5 inch Hard Disk Drive format is the preferred server format, while the 2.5 inch size is the preferred PC format.

In the 3.5 inch format:
Fiber Channel [FC] is anticipated to double, or increase from 5 million units to 10 million from this year out to 2010.
SCSI is predicted to drop from 20 million units this year to 15 million units by 2010.
SAS [Serial SCSI] is predicted to drop from 20 million units to 12 million units by 2010.
SATA is anticipated to increase shipments from 35 million units now to 60 million units by 2010.

In the 2.5 inch format:
FC jumps from 35 million units now to 65 million units
SATA jumps from 35 million units now to 65 million units
SAS jumps from 30 million units now to 55 million units

So SCSI, seems to be losing the server market, in either the parallel or serial format, while Serial SCSI [SAS] is increasing in the PC market [reduced cost].
Fiber Channel usage is increasing in both formats.
Serial ATA [SATA] is also increasing in both formats, which makes sense.

What does not make sense is that SAS seems to be declining, SAS uses the same interface as SATA so why the decline? I have to assume that the legacy programs still require the out-dated SCSI interface.