I was thinking the same. People see me as a jack of all trades, sometimes, and I really connected with some of the points the original poster made. But it's usually because the other person doesn't know a lot about whatever "trade" I'm doing at the moment, that they would call me a jack of all trades. Backend developers respect my backend work, designers respect my design work, etc, and that doesn't make me a master of none, nor you.
I'm an entrepreneur and I work for myself.