Well, I guess it will save them money…
I believe that the main story for this is less about the money and more about the history/nostalgia.
Keep in mind that this was the main TWA base. Hughes put a lot into services at MCI, STL, and JFK, and in the times since the AAL merger, most of the operations that were original TWA ops slowly dwindled away. IIRC, the STL ops are all but gone as well.
May be saving them money, but what is that compared to the last remnants of one of the first commercial airlines in the country, let alone the planet.
BL.
But it will still save them money… 
Ah young one. You have much to learn about business.
I think the main story for this is the LOSS OF JOBS!!! 
700 aviation related ones!
Did you notice Detriot was in the mix too. As if that city hasnt been hard enough.
Yes, master. I will get there someday, way, way…way away… 
Yeah, a little frosting for their cake.
Makes sense not to have line maintenance at a station like DTW that only gets 5 mainline flights per day.
MSP however gets 14 mainline flights and SJC gets 8.
Nicely put Tyketto! This is really all that’s left of what was TW. I was a part of TWA and remember the row of L10’s 767s and the 747 down the line of the C concourse at STL, not to mention the baby 9s and 72’s on the other side. Flight after flight, red and white, and the worlds best ever livery, the final TWA red gold and blue! It was sad enough to see it go as it was while still having AA operate a major number of flights, but now, STL is nothing. And as you said, it was one of the first major airlines in the US. The MCI MX base was huge for TW back when. Now its obviously just redundancy in the AA system. ThAAnks American.