Buy American laws/EOs are some of the most complex web of carve outs in existence.
In short, most of what is available in American stores is foreign made. With the Feds push to drive the overall expenditure down, buying COTS (commercial off the shelf) goods is actively encouraged (and COTS goods are exempt from Buy American).
Also, enforcement has never been the
greatest no matter who is in charge. Construction is usually an example that pols will use to show their willingness to use domestic goods, but Buy American laws define three zones that apply differing regimes. Under a handful of thousand dollars, doesn't apply. Between a few thousand and a few million, applies. Over a few million and it kicks into another web of contract law.
There's probably progress being made sure, but most of what we buy is still foreign in some regard. Most of the low hanging fruit was already achieved when the first revisions of the laws came around in the 30's and 50's.