Interesting read the fan thingy and great reasoning Mac128k.

Maybe they wanted to please those folks who thought like Jobs and didn´t want noise at least on one system of the line.

Maybe they simply "forgot" to update it.

maybe with other choices available in their line later, the reasoned that people would like to upgrade to newer models in case of major failure anyway.

I agree, doesn´t sound great my thoughts, but sometimes there might not be a significant reason behind things.