On assessing your own value, or the value of your writing:

This only applies if the goal is to make money and have a market determination of value. You might derive value from writing and thinking that is of even greater personal value than the market value.

Your early writings could garner no economic value, but they could still be building blocks upon which you will build later success - even financial success.

There are indeed many measures of value. I think it is dangerous to assess personal value in relation to anyone else though.... Of course, if the real goal is to make money and you aren't making money, I agree that some evaluation must be made. It more likely a practical matter than a value judgement though.