Not as much as you would think. The major of NRT routes have been replaced over SEA and DTW. NRT to the US is mostly flat on routes but again smaller aircraft. (more 330/777/767 no 747)
Everyone forgets all Northwest had that wasn't to Japan was DTW-PVG and SEA-PEK. Also it was post merger that routes like NRT-SGN, JFK, ROR and some others were started.
Plus added flying of ATL-PVG*/ICN, DTW-PEK/ICN, SEA-PVG/ICN/HKG Plus most of the NRT/HND-US flying is still there, IIRC only SFO-NRT has been cut so far.
On the flip side on the TATL market,
We (ATL) have lost CPH, ARN, TLV, ATH, SVO, VIE, MAN and routes like BRU, MXP, PRG are all seasonal now.
JFK has also become more seasonal and has lost some flights to places like MAN, ARN, SVO etc.
And a good bit of the "replacement" flying is going away. EWR-CDG, ORD-CDG, LAX-LHR and some others are all gone/shifted to JV partners.
No. Was talking about the PAX fleet.
The JV's didn't have anything to do with the 747-200Fs going away. That was due to the weak cargo demand and the general draw down of Asia crap flying NW did.