The Ukrainians do not expect American and other NATO troops to die for them. They fight bravely on their own even with outdated equipment. Early on in the war, the Ukrainian ancient T-64 tanks routed Russia’s famous 1st Guards Armored Army twice.
By now, however, Ukraine has amassed quite an armored force: in reality and in pledges. Most NATO countries have contributed, the Americans and the British in particular, not just tanks but also other hardware and training. For example, Sweden has dispatched both self-propelled howitzers and CV90 armored vehicles.