Travis Gafford's theory on IMT's departure.
https://www.youtube.com/watch?v=UZIQJawPNmM
He gives several reasons as to why he thinks this situation is NOT because of Overwatch, but instead, is because of the amount of money Immortals has been spending. Essentially, he thinks that Immortals are not monetarily sound.
He does, however, criticize Riot over not communicating this properly, which.....I have to agree to. I only found out about this because Travis' video was recommended on YouTube for me.