That is true, but what's also true is that it's _way_ easier to get promoted beyond L5 as a manager, and darn near impossible to get promoted beyond L6 as an IC. Google values managers more, just like any other company. That's why you see like 7 layers of management there by now and directors reporting to directors and VPs reporting to VPs: people want more money but can't get to the next level as ICs. Fun fact: when I left Google, I was 1 level deeper in the hierarchy than I've ever been at Microsoft, a company that at the time I left was twice the size of Google I left 7 years later.

I wouldn't say it's easier to get promoted in the sense that the work is easier. A company with 85,000 employees needs a lot of managers (who themselves need managers, and so on), so there's definitely demand. But that demand need not change the stringency of the job requirements.

Google could let half its managers go tomorrow and things would only improve. And you know it, even if you are a manager. :-)