Google decided to build a new chat app every two years instead of keeping the good bits of the original chat app they had and evolving it. It was endlessly frustrating to me when I was at Google. Google's security team ended up banning Slack access after several teams started expensing it.
It doesn't seem like building something that works well would be that hard; we've had nearly 40 years to learn from IRC, AIM, and others. Why can't I run my own chat client that does what I want? Oh, because you gotta lock people in. Sucks.
