The Army is not interested because helicopters are better suited for what they need. Simple as that.
Well, I don't think it's actually as simple as that. And bear with me for a minute here while I play Devil's advocate.
Since WWII (and to a lesser degree, Korea), the U.S. has not fought a large-scale war against a technically equal opponent. During the Gulf wars, the U.S. was against Soviet trained and Soviet/French equipped Iraqi forces, but certainly not on a level of the Soviet Union of the cold-war era.
So all the U.S. has been against in recent years, is assclowns in Afghanistan and Iraq playing cat and mouse in a low-tech hide-and-seek brawl.
We should not assume that this will be the face of warfare in the future, especially with Putin playing from Hitler's playbook and China playing the silent game over in the corner.
I give alot of credit to rotory wing aircraft, they have proven their value time and again on the battlefield but how well will the attack helos do against top of the line Russian T-90 tanks with their reactive armor, Kontact-5 ERA and Shtora countermeasures? And when Russian armor deploys, it is in a composite group that includes mobile AA batteries (like the BUK system) and is all well drilled and co-ordinated. With the T-90, comes the equally capable T-80 and upfit T-72.
On the other end of Asia, China has some serious stuff like Norinco's Type 99 and to a lesser degree, the Type 98. These forces are not a bunch of clowns wearing sweatsuits, yelling and waving RPGs or riding in the back of Toyota pickups armed with MGs...these are some serious contenders.
For attack helos to get into the mix with Soviet style deployments (ground forces supported by an AFV mix) would be a difficult and costly proposal without heavy backup in the form of a dedicated armor hunter/killer like the A-10. Which, by the way, would rip any of the afore-mention AFVs to shreds.
The armed forces need to stop and rethink the cold war possibilities and keep real threats in mind.