Winger Ibe signed from Liverpool for £15million in the summer of 2016 but left for free following the expiration of his contract this week.
Howe said: “When you look back and reflect, there is never one reason, I think there is a combination of reasons.
“I have said many times before that his ability and talent is undoubted - he has the ability to beat people, which is a rare quality in football.
“He has lots and lots of qualities, but it just didn't quite work here. I think that's obvious.
“That doesn't mean it won't work somewhere else for him and I think there are a lot of reasons off the pitch that contributed to that, rather than on it."