Among my TV jobs, I was a science reporter in a highly rated news show in Israel. Younger, more educated audience, relatively long attention spans and all.
Because the EP trusted my judgement, Science items on that show had 4 minutes max, which was very generous, considering that news items can be given 1:40-2:00 on 8pm news and 2:30 for late-night.
During those 4 minutes, every box of daily journalism still had to be checked:
• Is it clear?
• Does it explain why it's news?
• Is it informing people of an ongoing event they're familiar with?
• If it's entirely new, are they given enough context to make independent judgement?
Unfortunately, scientific content rarely checks these boxes. If you want to explain the LIGO gravitational waves discovery or the Higgs Boson discovery, you can't give enough background for the user to feel informed other than "scientists believe this is significant" - so it's only fit for print. If you want to explain a new discovery in 4 minutes, it better come with a demo, that demo better be rendered/filmed like a product video, or people lose interest.
So the science you end up covering is either from highly funded labs (think labs in Harvard and MIT that have DOD/industry sponsorship), or venture-funded companies with whitepapers and cool demos.
If you're lucky, you have a relationship with the labs, and you get to serve as their informal media adviser. I often met with professors for coffee to teach them to make press kits for their papers.
As a researcher, if you do market your paper, you run the risk of the press distorting it, as OP said.
tl;dr: science is slow and rigorous. News defers rigor to the extent permitted by law. Incentives follow.