Jantarei, 
Its not that Nikon is having hard time competing with Canon....There are lots of Nikon fans out there !

The reason for the price drop is because there's a rumor that new version of those cameras is about to hit the market around Christmas.

So market is expecting (Nikon D5200 (replaces D5100)..

Trust me, Nikon D5100 clearly wins those Canon T2i, T3i and T4i in low light conditions...It has the same sensor as D7000.