Why would you compare only goals scored? The main criticism for Antony is that he does not create chances.
Antony 3 goals 0 assists and 0,04 xAG per 90' (2 percentile for expected assists compared to other wingers and attacking mids!).
Grealish 2 goals 3 assists, xAG 0,33 per 90'.
Silva 2 goals and 5 assists, xAG 0,14 per 90'. To be honest I don't know how he got 5 assists, he always seem to be playing very deep when I see him.
So mentioning only goals is manipulating, since the total G+A is what matters. Grealish and Silva play in a better team, so it's pointless to criticise Antony for not matching those numbers, but I just don't think the argument you made is fair.
Anyway, if Antony kept scoring at this ratio I'd say its a good first season. But it seems very likely he will not, he massively outperformed his xG with those 3 goals in first 3 games so we have to be prepared he will struggle with numbers. His absolute lack of creativity is something that is quite bizarre though, hard to explain how can he have so terrible stats in that aspect of the game.