User blog comment:Berckley/Phase 2 theory/@comment-2041242-20150131020147

your theory goes against the information Marvel has given.

and there is a simple reason SHIELD didn't appear in IM3.

Iron man never asked for their help. He didn't expect to fight what he fought, so he didn't have the time to call in SHIELD. He had little time to react, therefore there was no SHIELD.