When you have Fortune 500 companies using you, you know you're not a startup or company for the common folk anymore. As for hostility towards developers, we only have to look at how well that worked out for Twitter when they turned up hositility to 11 towards their developers. Different situation, but same premise of cutting off developers making your product better.
As for Slack, I loved it in the early days. But now, I find is distracting. The numerous bots you can enable on it (most of which are counterproductive) are annoying or distracting (like the Gif bot). I dread opening up Slack because it's not a nicely designed product and it is starting to become dated.
We've been using Microsoft Teams where I work and I must say that it is amazing. You get so much out-of-the-box with it without needing to add in bots and it's more customisable.