Yeah, many engineering blogs fail because of content reasons, not organisational ones. In many of the smaller places I worked at there weren't any institutional obstacles to posting content to the blogs. It was a matter of not caring much about the blog or writing the wrong content (stuff that isn't helpful or interesting).

For a successful corporate blog (engineering or otherwise), writing blog articles needs to be a foundational part of the company culture, the different teams must work together to create the best/most useful content possible, and there must be a schedule beyond 'whenever we feel like it'.