Very true. As I've been studying this topic lately I can even provide you some hard data.

A financially stable newspaper gets around 75-80% of its gross revenue from advertisements. That's why advertisers have so much power over content, even news content. I don't know the exact figure for magazines, and it could very well be lower, but this should give you an idea.

In fact if you check the literature you'll see that a common idea is that newspapers are in the business of selling customers to advertisers, and they will try to attract a certain type of reader in order to get certain type of advertisers.