They had a more pressing requirement for transport/utility helicopters. So the Apaches are upgraded instead, and more transports on the way... modern Chinooks (CH-47F), Blackhawks (all kinds), and UH-145s are coming, and I think they also ordered some additional AH-64Ds. I think it was a good decision, but maybe it would have been better to postpone it, instead of scrapping it completely. You'll need Apache replacements some day, but maybe they are counting on UAVs for the job by then...?