Not denying this but how is this so? I'm not very well informed on this whole situation..
Shia muslim groups have gained strong footholds since the Arab Spring movement and the US wars, in Lebanon for example Shias now have a significant influence in parliament, in Iraq Saddam's removal increased Iran's influence in the region, Syria is Iranian backed and aided by Shia groups, Yemen continues to battle Saudi Arabia etc... The Sunni's influence has taken a hit in recent years increasing Iran's influence.
Iran are one of the few Muslim countries who are mainly Shia Muslims most of the middle east were Sunni but since a number of significant leaders have been toppled Shia groups have began gaining influence.