The US (and the rest of NATO) is being cautious for a reason, and it's not because they're using Ukrainians as "meat shields."

NATO stocks of war materiel were at historically low levels before February 2022, and it's difficult for the US to commit fully when China is sabre-rattling over Taiwan. That's Xi's (and Kim Jong-Un's, to a lesser extent) gift to Putin. Sabre-rattling keeps the US from engaging fully in Ukraine, even though China won't be ready to invade Taiwan for several years yet.

Unfortunately for Ukraine, it'll be several years before NATO materiel stocks start to grow above 2022 levels, but they will grow.

The question is, will they grow fast enough?

Personally I'm predicting world war in 2027-28 unless the West pulls its finger out.