10% is about the best return you can count on (very optimistically) I don't know what country you live in, but 10k in the US, even for a single person, would put you far below the poverty line. No way you could afford that dental work after you pay rent on that. And let's not even talk about all of the other huge expenses that will come up later in your life.
$10m * 3% = $300k/year
That's a high end salary in the US. You could cut this number in half, and that would be ok too IMO. Less than some developers make. But you can buy a reasonable house, car, etc. Not a farrari though, unless you're irresponsible.
If you actually intend to live on this money forever, then the return you receive is really the maximum you can spend. And that's really not as much as you would think. Especially when you figure there will be some years where you won't earn anything (during recessions).
Again, if you live in an expensive country like the US. If you live in a poor country, maybe 10K is enough. But this article and these numbers, aren't really about that situation.