The background is explained in the Wikipedia article:
On May 14, 2010, NBC canceled the show, opting instead to pick-up Law & Order: Los Angeles for a first season, and renewed Law & Order: Special Victims Unit for a twelfth. The cancellation was announced after last-minute talks between NBC and Dick Wolf to extend the series failed to lead to an agreement.
David felt — and I agree — that the headline writer probably meant (what most English speakers would express as) "cut short" rather than "caught short", and either mis-learned the idiom, or else committed a word-substitution error under time pressure. But maybe, David wrote, the English language has changed and he missed the memo.
The common idiom to be caught short [of X], usually used in the passive form, means something like "to find oneself unexpectedly with an inadequate supply of X". A few recent examples from the news:
No commercial firm wants to be caught short of supplies should China come knocking with a larger order.
I have to say city were the last team I thought would have been caught short of players this season
He delivered a corner to the far post where the Thais were caught short of defenders and Mphela was on hand to bundle the ball over the line.
Mega-rich Tony Blair was caught short of cash when he could not pay a train fare.
Today, most people are now resorting to this kind of loan in order to get some financial relief when they are caught short of cash.
With last fall's flu season approaching, the U.S. was caught short of vaccine when the British manufacturer was shut down
When the Financial Panic of 1893 caught him short of cash, ironically he himself was forced into bankruptcy,
The idiom can be used with the of-complement left implicit, as in this quatrain from a poem by Sean O'Brien, Never Can Say Goodbye (with apologies to Gloria Gaynor) :
49 Because you write but never read,
50 Because you never listen,
51 Because you are the porcelain
52 The caught-short Muses piss in?
But "caught short "also has uses with a more literal meaning, often in sports contexts. For some reason, this is especially common in writing about cricket, in the specific collocation "caught short of the crease""
Johan van der Wath is caught short of the crease by Dinesh Karthik.
The Australian was caught short of the crease by Ambati Rayudu's direct throw as he responded to a non-existent single call from Fazal.
But we can find similar expressions in baseball, football, etc.:
…he chased down that pass interceptor for 90 yards, wouldn't quit and caught him short of the goal
…but a strong throw by Cardinals Jim Dwyer caught him short of the plate.
So might the headline writer have meant "caught short" in some more literal sense, since the show was "overtaken by network executives before engaging in the traditional interactions between writers and fans that are expected during a long-running and popular show's final season?"
Maybe, as is sometimes the case in apparent word-substitution errors, the writer's intent was a sort of superposition of the caught/cut connection and the literal sense of being overtaken by opponents before reaching some goal.