US 'cannot locate Iran's missile launchers'
US forces have been unable to locate all of Iran’s missile launch sites, officials have disclosed.
Donald Trump, the US president, told CBS News on Monday that the American-Israeli war with Iran was “very complete, pretty much”. He added: “We’re very far ahead of schedule”.
However, Iran’s missile attacks have continued, and two unnamed military officials have claimed that the Pentagon does not have “full clarity” on all of its enemy’s launch sites, according to The New York Times.
The sources said that Iran had “kept many missiles in reserve to strike at important battlefield targets like the American radars” designed to identify threats.
https://www.yahoo.com/news/articles/us-cannot-locate-iran-missile-153630678.html
= new reply since forum marked as read
They're also probably well-camouflaged.
So, bring 'em out, shoot for 2-3 mins, hide 'em back underground. Hell they might even have subterranean networks to move them around in entirely out of view. Can do the same with drone launching systems.
Just a guess but they've had a long time to prepare and the logic for doing so seems fairly obvious 
