Have yet to see this in practice. What usually happens is a bunch of articles are written "condemning" their actions, they are fined some ridiculously small amount and then business continues as usual.

The most recent action that seems to have had a significant impact on how Facebook captures data is Apple's "Ask App Not to Track". This is not exactly a shining example of the how the US system protects users privacy as the action was taken by a company, not a regulator.