Well, he was.
Officially sacked today. As I said before, it is never easy managing Inter. I really didn't get De Boer's appointment to begin with. They have chosen a coach who doesn't know the language, didn't have coaching experience outside of Holland, has a very different playing style compare to Mancini and his squad, and looked quite naive adjusting and learning from his mistakes. Sacking Mancini 2 weeks before the season starts was a big mistake. The new players arrived very late. The club didn't address the team's weak spots very well. They went and signed fancy players but the most crucial positions remained untouched. The squad is very imbalance.
I sympathize with De Boer tho, as I do with pretty much every coach post Mourinho. The club keep hiring different coaches but do not give 'em proper elements and fair time to deliver. They keep average and aged players around while freezing young and hot prospects on the bench or in the stands. This is a mess that needs to be fixed from the roots. Coaches make mistakes and have their own limitations, but from Benitez to De Boer, none of 'em were given sufficient support from the club to prove themselves.