"If you are not providing binaries then there is no need to provide source."

The intent behind "Open Source" is not to prevent suppliers of software from withholding the source, it is to facilitate innovation. The entire goal behind licensing a product with an OSI license is that other people will help the author improve the software. If people are choosing to release their software with these licenses for some other purpose, that is their prerogative, but the INTENT is specifically to benefit the greater good of the masses by ultimately providing a better product through the community effort.

To that end, as the author was implying, Google et al are not REQUIRED to 'give back' any of their changes to these projects, because they are not re-distributing the modified products. However, the spirit of the license is such that, you're given permission to use the product gratis, so if you do improve it, out of appreciation, and in an effort to continue the evolution of that product, these companies should send their changes upstream. As noted previously, though, the entire 'community' is based on the honor system. If they choose not to be good members of the community, they do have that right.

Quite a lot of people outside the open source community have a misbegotten idea that open source software and open source licenses were created specifically to 'give the finger' to big business, or some other related silly notion.

Yes, much of the rationale behind the new GPL v3 IS to counter predatory business practices, and some parts specifically aimed at microsoft, but the original intent of these types of license is simply to foster the community development concept... and as the years have shown, aside from some fractiousness within the community, it has been largely successful.