Do you think IBM, Apple or DARPA care about a blog and a popular fanfic? Do you think that you can even talk to DARPA without first getting involved in some amount of politics, making powerful people aware of the risks?

Organizations are made of people. People in highly technical or scientific lines of work are likely to pay less attention to social signaling bullshit and more to actual validity of arguments or quality of insights. By writing the sequences Eliezer was talking to those people and by extension to the organizations that employ them.

A somewhat funny example: there's an alternative keyboard layout, called Colemak that was developed about 5 years ago by people from the Internet and later promoted by enthusiasts on the Internet. Absolutely no institutional muscle to back it up. Yet it somehow ended included in the latest version of Mac OS X. Does that mean that Apple started caring about Colemak? I don't think the execs had a meeting about it. Maybe the question of whether an organization "cares" about something isn't that well defined.