That's not true, and certainly not true enough to make such sweeping generalizations.

From the actual New York Times regarding their editing standards for writing headlines: [1]

  Headlines are written in the historical present
  tense. That means they written are in present
  tense but describe events that just happened.
  The exception to that is when you're reporting
  on something that happened quite some time
  ago."

The Rosetta Stone wasn't just deciphered.

[1] https://archive.nytimes.com/www.nytimes.com/learning/general...