I'm acutely aware that 500 Kanji isn't nearly enough to read even the most basic of texts, unfortunately... But considering it 'only' took me 1.5 years to get to this point at a leisury pace, I would assume that anyone should be able to get to ~2000 Kanji within 2 years if you really put the effort in. If you get to JLPT N5 (~2000 Kanji) you should be able to read anything but Japanese literature. Don't know how this works for Mandarin or other Chinese dialects, but I would assume there's a base set of around the same size that should be sufficient for daily life.
The article title was implying the Chinese writing system is a 'brake on development', which IMO is nothing but hyperbole, and neglects that logographic writing systems also have their advantages.
Consider that 500 kanji is equivalent to about 3rd grade of elementary school, you need to know much more to read most texts. And as you learn more, they become more and more similar-looking.