It says 'collect salary' not collect free money.

Isn't the job in the game getting rent from people?
(It is)

No, it's to drive everyone else into poverty.

But they still get the 200 when they pass go!

Not if they go broke an lose. The game itself is meant to be anticapitiaist.
https://www.bbc.com/worklife/article/20170728-monopoly-was-invented-to-demonstrate-the-evils-of-capitalism