I'd like to agree with this one. The bulk of the market is in the low-end, but the low end is going to be reluctant to embrace anything unusual. Sicortex uses mips processors, which means you can't use your off-the-shelf applications. Even if the rack of intel blades uses more power, and takes up more space, a low end cluster still isn't that large, or that power-hungry. You're not talking about building a whole new building to house the machine.
The high end, where custom applications rule, is more likely to embrace a custom architecture; Cray vector, IBM power, Itanium still play in this arena. However, the largest sicortex machine really can't play in the big leagues. 5000 low-power mips processors is a pretty modest cluster, even if the network is good. The big leagues also means you're dealing with the established HPC customers, who are very demanding on the software and service front.
The low end has a lot of market, but the competition is fierce, and the margins small. The high end requires a lot more infrastructure than an 80 person company can provide. In all cases, developing a new processor is very expensive. Intel and AMD spend billions of dollars designing each generation of chips, and have the tools to build them with full custom logic, instead of asic designs. Once sicortex invests all that money in designing the processors, they still have to build a machine around that. Then you have to build a software stack and service organization. Then, you have to sell the thing into a competitive marketplace.
Tough row to hoe.
The low end is a larger market.