Primarily, the acts expired naturally, per their own wording, after two years for the Alien Act in 1800, and after March 3, 1831 for the Sedition Act. The Alien Enemy Act has no expiration date, and continues to remain in effect today. It was last used during World War 2 to intern German-Americans, Italian-Americans, and most famously, Japanese-Americans.

The Alien Act and Sedition Act are no longer used because they are no longer in effect. The Alien Enemy Act would probably prove very unpopular if put into use today, unless there is a large change in American sensibility. The last time it was used resulted in decades of lawsuits, formal apologies by the government, and re compensation. It is likely that today's Supreme Court would overturn the Alien Enemy Act should it be invoked again except in small and specific circumstances of dire need. As a result the government probably prefers to keep this ace in it's pocket for emergency situations that may arise in the future; though, this is a bit of speculation on my part. It cannot be overturned if it is never used.