Why Slack might make many startups and technology simply disappear

Slack is one of those unicorns. It's never just one thing that makes them change the game, it's typically a combination or recipe or things, such as brand, team, design, and customer experience. In their case security also plays a big part. They have essentially taken the concept of ICQ, made it consumable for everyone, and giving it a layer of security.
When reflecting on my daily tech habits these days, Slack has grown to take up a significant portion of my spend, and I don't mean tech spend, rather where I spend most of my day when using tech tools. I spend 90% less in my email account and all file sharing and communication is there. Slack has become the glue and replaced many products I once used.
Bottom line is, I need significantly less other technology tools during my day, and this means some of those tech products and startups will simply disappear.