EDIT: Also, at the end of 2009, TRIM support was just hitting the market, and SandForce-based drives were just being announced. Since then, TRIM has become universal, as has 6Gbps SATA support, and most controllers have been through at least one other iteration. SSD caching has also hit the market in a variety of forms.
3 years is a really long time for an entire industry to be totally stagnant. It's somewhat similar to how Intel has been sitting on their asses for the past few years ignoring the entire mobile computing revolution.
You seem to be under the false impression that the NAND is the most important part of an SSD. It's not. From an engineering perspective, it's the least important component - it just happens to be the primary reason for cost scaling with capacity. The controller and it's firmware are far more complicated, and make all the difference for performance. Those components have made a lot of progress in the past three years. And even the NAND has advanced, just not exponentially, because while density is inversely related to unit cost, it is also inversely related to durability, and the drives 3 years ago weren't designed with excessive longevity requirements.
http://www.amazon.com/OCZ-Technology-2-5-Inch-Performance-OC...
AFAICT, the OCZ Octane is the only 1TB 2.5" drive on the market, but I suspect you'll start to see more of these later this year (at slightly more sensible prices, one would hope).
$1270 for a drive that is essentially a RAID-0 of two 512GB SSDs, packaged in a single 2.5" drive. OCZ also has the Colossus drives that offer 1TB as a RAID-0.
Seagate has a 4TB disk; they were probably about to release it when the floods hit so I guess they decided to wait.