That role is outdated: the US realistically does not expect a full-on war with Russia (though a hybrid war is a possibility, such as the Ukrainian conflict). Also, sending tanks in a single file column down roads is stupid. Russia knows this.
What else can it do? Someone mentioned Close Air Support. The AC-130 and MQ-9 do it WAY better. The gun on the A-10 can't hit anything accurately (remember - to aim the gun you have to physically aim the aircraft - the A-10 is not a nimble plane, and human targets are TINY at altitude). The A-10 can also carry bombs for Close Air Support. The thing is... so can the MQ-9 and AC-130. the MQ-9 can loiter on target longer and is WAY cheaper, and the AC-130 has missiles AND guns that actually hit things AS WELL AS quickly engage targets.
Can it kill tanks? Yes! But if you're taking out tanks onesy-twosy (again, not in convoys), then again, so can the AC-130 and MQ-9. The Hellfire was LITERALLY designed to kill tanks. Great thing about MQ-9s too is that they're remotely piloted; in a neer-peer conflict, the tanks would be protected by AA - but there'd be no pilot deaths if an MQ-9 goes down, so you can send them to risker places.
It's an outdated plane for an outdated mission set that's expensive and ineffective for what it does. People just REALLY like it because "it's a flying tank!", and "brrrrrt! haha! Big gun!". In the end, it stays around solely because of it's "cultural value".