Because at the end when Thanos kills half of everyone, Scott's already no longer under house arrest. Seems like they'd hear what was up instead of doing experiments.
shareApologists have said the plot of IW just last a couple hours
shareIW as far as America knew was only a few hours. All the average person sees is that a ship landed in NYC and Stark disappears. That entire sequence is only a few moments. Also in IW they decide not to get Scott and Cint because they are under house arrest and have families.
At the end of IW, Fury had no clue what was happening. Maria says multiple bogies over Wakanda. Then the effects of the snap. We know all that has happened because we witnessed it.
All anyone, including the gov't, knows is that a ship landed and Stark is missing. they dont know about Thanos, they dont know about the gauntlet or anything.
Only the rogue Avengers on Earth know what is happening and Ross only cares about arresting them. The US gov't and the media had no fucking clue what was happening in Wakanda, Titan, etc etc.
In fact the Rogue Avengers in Wakanda have no idea Tony is alive. They assume he is dead or gone. They are all split up and fractured.
Now in the middle of all this mess, finding Ant-Man would be negligble. At the Avengers HQ they flat out state he is under house arrest.
Also, Ant-Man isn't technically an Avenger. Even in this movie Hank says Scott was ''fighting the Avengers".
Also where was Ant-man going to go? Remember after his hosue arrest he is on parole. He decides to go to NYC and there's nothing there lol. He gets there and no one knows where Tony or Spidey etc are. No one knows the Avengers are in Wakanda. So he just walks around while he is on parole? And remember Hank and Janet are still wanted fugitives. They aren't going to risk going to NYC to find out what happened. Pym hates Stark. Even if they saw what happened... all they know is that NYC was attacked and then left. For all they know it's all over.