You apparently are out of the loop ... this was announced months ago by Skyteam as a coordinated effort to reduce TATL capacity. Not all of the cuts from all of the Skyteam members have been released but the list is pretty close to being finalized.
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You might also want to know - if facts matter to you - that the percent of DL cuts at JFK and CO cuts at EWR are very similar. The difference is that CO flies many routes wiht double daily flights during the winter so they can downgrade a market without exiting it. JFK during the winter to Europe is a very low yielding market which is why DL is keeping many of those markets that have service to ATL operating.
Yields via ATL are high enough and there are enough connecting opportunities that DL can afford to operate many of the flights given the higher fuel prices.
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You also failed to note in your copy and paste from airlineroute that other airlines are doing much of the same cutting.
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And you also failed to copy the restart of many of these same flights beginning in the spring.. some of them as early as March 1... and until then, you might want to look for the additional flights which are being - and will be added - to non-European destinations during the winter.
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oh, and DL has another year of aggressive cabin refurbishment coming up this year.... I believe the 744 and part of the 763 fleet is supposed to be upgraded this winter.
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Sounds to me like DL has every intention of sitting out the weak revenue environment and come back ready to make money when it makes sense to do so....
and in the next few weeks there will be several new routes announced for next summer.