If jefftk wanted to stop working on ads, he could transfer within weeks to any of hundreds of open positions on Google's internal recruitment platform, keeping the same compensation, benefits, etc. It's stupidly easy (doesn't even require your current manager's approval!) and the only "cost" is usually that it can set you back slightly in your career due to abandoning your current projects and having to ramp up on new stuff.

So no, "because of the salary" doesn't explain any of it, and you should read the blog post before posting insulting comments like these.