it is easy to get published if you write for nothing.
I would be suprised by that.
If one takes the circulation of a typical news-stand flying mag and multiplies it by the issue price, and subtracts the likely cost of the print run, the cost of paying for contributions, say £100 per page, ought to be not too significant.
So I cannot see their decisionmaking being guided by whether they get content for free.
People will always be pleased to get into print for the vanity of seeing themselves published.
There may be some of those, and I suppose everybody likes seeing themselves in print, but I think a bigger motivation in this field (flying) is to help others got more out of it. That is certainly mine. Nearly everybody chucks flying in within a year or two, and one of the main reasons is a lack of knowledge on how to go somewhere.
Travel writing I know nothing about, and I suspect there is a lot of free stuff involved. I think books like the Rough Guides / Lonely Planet get most of their ongoing content for free. But there is a vast amount of free travel info on google, anyway.
I don't see any way to keep a lid on any mainstream-activity information being online for free - regardless of what journalists might think of it.