if Breath is represented by literal Wind then Blood should be represented by Earth?

That’s a fair association, specially because Breath is a more Free and Detached Aspect, compared to Blood which is more Grounded in actual attachment to other people and tangible bonds. However, you’re also thinking in Elemental Terms. Breath is Wind because Breathing moves the air, likewise Blood’s literal facet would be more actual Blood rather than Earth. In a way it fits too doesn’t it? Breath is physical, lung-filling breathing, while Blood takes on the more cell breathing sense, with oxygen being carried by Blood.