This is easy to explain
Here's my 2 cents.
Firstly, FCOE made promises about convergence - simplifying the data centre.
You can get simplification from iSCSI, firstly at 1Gbps and now at 10Gbps. And unless you're really looking for very high deterministic performance, iSCSI can hang with the big guys. iSCSI continues to grow - rapidly - due to its lower cost, simplicity and good enough performance for the majority of applications (consolidation, virtualization, near-line archive, backup to disk, etc).
So why Fibre-Channel's continued popularity? Several reasons.
Firstly, the FCOE protocols have just been settled, but the Ciscos, Junipers and Brocades are all arguing about 10Gbpe lossless Ethernet connections, with little common ground.
Secondly, converged network adapters (CNAs) only started to appear on the market in late 2010, which slowed growth. The article mentions blade servers, but if you recall, rack server introduction of CNAs came first and only in late Q4, early Q1 were the blade form factor CNAs introduced for a couple of the major server vendors.
Thirdly, fibre-channel introduction of FC8 protocols offered deterministic connectivity at speeds (really capacity) similar to 10Gbps FCOE..
Fourthly, a storage architect who has built his reputation on 12 years of fibre-channel is going to be highly skeptical of ripping and replacing for something so new.
Fifthly, has anyone seen the cost of the Cisco Nexus gear that you are expected to roll out should you go this direction? in the current climate, that's sobering enough to make you extend the investment you've already made for another business cycle...