Well, I'm a backer of Limit Theory also and even if Josh Parnell has my admiration and support, his development videos cannot compare with the amount of information CIG is releasing. And he couldn't if he wanted to. He's just one guy. The other games you mention I have no experience of.
That's the thing people seem to be misunderstanding. Sure CIG releases a lot of videos, but that doesn't necessarily equate to a lot of information. Josh may only release one or two a month, but his videos are very information dense. But not only that, he has his daily dev-blogs on the forums, his summary blogs on the website, and the Kickstarter writeups, making his project quite possibly the most information-dense game development project I've seen in a while.
Planetary Annihilation didn't have quite as many writeups, but the ones they did have consisted of detailed information on the engine, replay systems, AI, pathing systems, etc. As in, you could write your own RTS engine and use these writeups as an implementation reference. Heck, one of the developers even gave a TED talk about some of the AI work he was doing. And then, of course, there is their regular forum participation, in which just about every single dev has posted in at one point or another.
If you're looking only at videos, then yes, CIG is likely unsurpassed with regard to their output. But there's only so much information about the development process that a video can show you. If you want actual information, text writeups are a much better way to go. In fact, that's why I don't bother to watch any of the videos, and why I get annoyed whenever people are posting CIG videos as answers to questions (like several posts just above, no offense to the original posters.) They rarely provide anything new or informative, whereas reading one of Josh's shorter daily dev blogs is always guaranteed to enlighten. (And also make me jealous of his output as a developer.)