The US Department of Justice is suing Apple for “monopolizing smartphone markets” to help guarantee the iPhone’s continued success — to the detriment of consumers and third-party developers. The suit was filed on March 21st and will take a long time to play out. It touches on everything from iMessage lock-in and App Store developer fees to “super apps” and cloud gaming. If the government is successful, we could witness a sea change moment for the iPhone and Apple’s ecosystem at…