goodroi - 4:39 pm on Aug 9, 2013 (gmt 0)
According to these guys who actually did scientific research [law.berkeley.edu...]
Google has a presence on:
73% of the top 1000 sites
37% of the top 25,000 sites
I would guess that percentage gets significantly lower when you look at the top 1,000,000 sites.
Since most websites do not have a Google presence, Google can't get "100% of the website visitors via GA for free" regardless if you place Google Analytics on your single website.
If you have thousands and thousands of dollars then you can afford to buy your own analytics solution (I doubt most people reading this have that money). Not to mention that 73% of the top 1000 sites have chosen to allow a Google presence on their site, so just maybe it isn't all bad.