The way I read it, the author was explaining his expectation that Facebook would beat Google to implementing that model. This then emphasizes his misunderstanding of the point of that quote about building it before others. Even when agile about specific features, the inertia of Facebook's existing core product can be hard to overcome; entirely unsurprising given their huge userbase. Google was effectively starting from scratch.

Google has a lot of work to do, but with a mostly blank slate and less inertia to overcome. It's also remarkable how they have used this as an opportunity for improvements across the board, a the very least visually.

I have to agree, I don't find the analysis or the train of thought particularly insightful. It seemed apparent to me that facebook being 'unable to change their core product' meant exactly what he figured out it meant 6 paragraphs later... not that they couldn't do it, technically.

Also, does he understand the extent to which Facebook actually uses PHP? "quick, adaptable tools like PHP" ... um... seriously?

I stopped reading exactly there.

Believe it or not, it is possible for Facebook to be lean and agile yet produce a less than compelling response to circles. Google's internal process has also been criticized before by other former employees, such as the infamous color survey. Your eagerness to dismiss an account from someone on the inside is a little weird and doesn't refute the points he made.