There are copious amounts of analysis as to the fall of IT, an alliance that had fallen on hard times but was still secure in its home regions yet still entered a tailspin. Being removed from the politics directly I can only observe and read about what others have said, like Mord Fiddle or Easly Thames or the promised report from Mansai.
However, I do think I can offer some 20/20 hindsight opinion from a removed position. Take it all with a grain of salt.
Last year when IT formed it was obviously BoB 2.0 with the goal of fighting the Goons for Delve. Forcing Pandemic Legion out of Fountain (which in the long run has probably been good for PL) was only the start of the invasion, the staging ground for the assault on Fortress Delve. The massive alliance had formed a gestalt around the goal of fighting Goons, it was the unifying concept.
When the Goon imploded, it took away the fire in which IT needed to forge itself into an alliance with a common touchstone. They completed the objective without the blood sweat the tears needed to make it truly a victory.
There was another attempt to create a touchstone, the infamous Max 2.0 assault on the Northern Coalition. Due to many factors, that failed and in turn only created further divisions in IT and its allies.
But all of that is only prelude to the real tipping point: When Against ALL Authorities was facing tremendous difficulties with Initiative and friends attacking and internal struggles, did former ally IT send reinforcements or words of encourage or offer refuge? Sadly no, the divisions of the failed Max 2.0 and other pressures caused IT to abandon its previous relationship and choose to attack the vulnerable rear of AAA. Not only did they lose an ally and make them an enemy forever, they lost e-honour (such as it is) in the eyes of the rest of the cluster and perhaps even internally.
Consider the ramifications of that decision. Fast forward to this winter with TEST and Goons invading Fountain and AAA resurgent pushing the Initiative out of Catch. Faced with pressures on two fronts and unable to win on either (due to NPC stations or numbers) the alliance fractured. Had they supported AAA even a bit (such as offering space in their vast holdings to rebuild) its possible that one of the fronts could have been placated and they could have focused their attention fully on Fountain, possibly finally giving them the touchstone to solidify the alliance.