It's impossible to replicate the informality via either email/IM or phone. It's spotting someone who is between tasks and bouncing an idea of them.

My company and team have

* a post-standup, periodic “coffee time” meeting my team has

* multiple random channels my team and also company has, with such topics as ‘allow developers to yell, all messages here must be in all-caps-rage’ as well as a literal regular random channel that has lots of memes

* an open, inclusive and encouraging culture where people promoting ideas at a team or department and possibly even company level is commonplace and encouraged.

We haven’t had much of a lack of culture and idea generation. I’m sorry you’re suggesting you’re not experiencing this.

It’s not. This is purely a cultural issue.

Sure, if we can instantly change all of human culture and psychology, it's not a problem.

In the real world, however...