There is some dirty secret i learned in my time as a eng. manager: Working in open source / Being the maintainer of a popular library / Blogging about software: All this things won't give you necessarily a competitive edge but can work against you. It's counterintuitive but sometimes teams are looking for a more low-profile hire.
This is cope and propaganda to discourage people from developing their own brand. Better for the corporation if the workers have no support structure or reputation that might lead them to quit
This is such a US-centric cliche that it even reads as a parody. No, the man isn't keeping you down.