Contactless has made great strides in the U.S since 2015. I'd say 90% of the terminals take contactless now.
The problem is, we still have a group of people that prefer using cash, yet alone, want to use contactless. Heck, we have people that still ask to pay with checks and then get all huffy and puffy when we don't accept them.
Cash is used in USA because the USA dollar is king currency of the world.