The "work hard" isn't meant as capitalist propaganda. Well, at least it didn't start as such.

It was first and foremost an advice given from themselves because drawing manga and anime was seen poorly and a dead-end job. The creators faced a lot of opposition and few opportunities, so every success was heartfelt and attributed to them working hard for their dreams and not giving up.

Despite entering the mainstream having diluted the situation these words were meant for, it's important we don't forget that the first creators were pioneers who dedicated their entire lifetimes to their craft.