Your positing that its about money might be correct, but for different reasons than you suggest. News and magazine publications often do link to a number of different documents. Many articles published are written pretty quickly and cheaply these days due to the demands of "no paywalls" and advertising that doesn't pay enough.
The situation isn't so black and white.
See: https://www.win.tue.nl/~aeb/linux/hh/thompson/trust.html
Wow, that's uncalled for, but moving on.
I actually know a lot of journalists, so I'm familiar with the way they work.
Even though they don't include hyperlinks, most of them go to great lengths to ensure the accuracy of what they write about.
Also it's a bit naive of you to assume every piece of source data has (or even could have) a URI.
While this is not a bad idea, it's not possible for a variety of reasons from the purely technical to the practical.
In a way, many traditional reputable news organizations are guilty of perpetuating this lack of expectations among readers. It's still common, in this age of hypertext, to see major news organizations publishing stories online that don't have hyperlinks to the source documents. Presumably this is motivated by money; they don't want to send people away from their site, or an old newspaper mentality where hyperlinks didn't exist at all, but it's inexcusable in the modern digital era.
When reputable news organizations neglect to link to source documents, it provides cover for fake news organizations who also don't link to source documents by normalizing the appearance of articles that do not link to sources.
Here is a counterexample, of the NYTs actually doing the right thing: https://www.nytimes.com/2019/05/13/us/politics/supreme-court... In the first sentence you have a hyperlink to the pdf on supremecourt.gov. This should be the standard for modern reporting, but it seems to still be the exception rather than the rule.
On the other hand here you've got a New Yorker article talking about the same SCOTUS decision that contains no hyperlink to supremecourt.gov: https://www.newyorker.com/magazine/2019/05/27/the-abortion-f... Arguably in this case it's because they're stuck in a print mindset, but frankly I don't think that's a good excuse.