Marketers market products. And marketers also market marketing.
Some are good at the former, few even understand that the latter is just as important.
To market marketing means promoting the role of marketing internally. It means asking around what the expectations around marketing are, kicking off a dialogue, setting and reporting on the right metrics, being consistent at building a narrative that supports all of the above.
When marketers do only market products, you see marketers going around and trying to apply the same tactics in completely different circumstances. Then coming up with a new fad to try and keep things fresh.
Marketing is a practice, not a campaign.