Rusting In Peace - You are correct if you just look at the current crop of PCI-e based ssd's designed for consumers. You should see what's coming from the business enterprise side of the market - near memory speed data storage. As usual, the problem for consumers, enthusiasts, and gamers is price. The performance of consumer grade ssd's was restricted to keep prices down. The same thing will probably happen with PCIe 3.0 based ssd's.
Base Clock Speed: PCIe 3.0 = 8.0GHz, PCIe 2.0= 5.0GHz, PCIe 1.1= 2.5GHz
Data Rate (per lane & per direction): PCIe 3.0 = 1000MB/s, PCIe 2.0= 500MB/s, PCIe 1.1= 250MB/s
Total Bandwidth (x16 link): PCIe 3.0 = 32GB/s, PCIe 2.0= 16GB/s, PCIe 1.1= 8GB/s
Data Transfer Rate: PCIe 3.0 = 8.0GT/s, PCIe 2.0= 5.0GT/s, PCIe 1.1= 2.5GT/s