I think the main reason why Sun continues to sell non-X86 servers is due to application lock-in and familiarity with the company/sales team.

Quite frankly, just about every test I've ever seen, implementation I've ever looked at has shown Intel X86 running Linux as better performance per watt that a similar Sun architecture and significant price-performance over Sun.

I'm not familiar with the very high end product line E12K, E15K, etc. but again, those architectures that are able ot be moved can be moved and the resultant savings to the customer are immediate and significant.

Sun isn't as fortunate as IBM to have a lot of proprietary banking and medical applications written for (and ipso facto supported on) its Unix platforms. Thus, Sun is more vulnerable than its competitor in the market space where it's still able to make a few roubles. I suspect this is the reason why Sun has changed its stock ticker from SUNW to JAVA - it's ultimately planning to get out of the hardware business.