Necessary, Sufficient, and Causality (or Adventures in Publishing)
For example, having an internet connection is necessary to get online. It is not sufficient, though - you also have to have some kind of device that can use the connection.
Pretty straightforward. Then you throw people in the mix.
Having sex is necessary to get someone pregnant. But it's not sufficient - you can have sex lots of times (or ways) without pregnancy occurring.
Oh. Wait. Sex isn't actually necessary either. Artificial insemination and all that. So we'll say that getting a sperm and egg cell together is the necessary --
Right. Cloning. Parthogenesis. Those are necessary for one way of making babies... but not necessary for other methods. So it starts getting complicated.
And that's just biology.
It gets really complicated when you start looking at sociology or economics. Especially something that's craft and/or art dependent like publishing. Our brains rebel. It's too much to deal with intuitively. And that's when the crappy advice really starts flying.
Think about any of the strident folks who insist their way is the only (or even best) way to publish. They're usually talking about one of the reasons they succeeded. But the reason they're talking about almost certainly is not sufficient by itself... and may be counterproductive for the way you are going about getting published.
There is no single sufficient or necessary element to being a successfully published author.
Read that again. It's important.
There's lots of things you can do that will raise your chances. There are other things you can do that will hurt your chances.
Want evidence? Check out the First Novel Survey that Jim Hines did (along with the further analysis of the data I provided).
Stop focusing on things like sales, or acceptances, or downloads, or hits. You can keep trying to tweak, trying to find that one sufficient element that simply doesn't exist... and lose track of why you're doing it at all.
Focus on goals you do control. How many words have you written? How many submissions? How many articles? How many queries?
Meet those goals. Keep meeting them. And do it again.