Chat apps have been around for literally decades. There’s plenty of prior and current competing apps that do essentially the same thing and use a fraction of the resources.
Very few prior apps did what Slack is doing [1] And there are not that many actual competitors if you start counting them.
[1] It's still strange to me that many people compare Slack to IRC and XMPP and complain that they were doing all the same things, why have people abandoned them. Even though they (and especially the clients) were doing (or capable of doing) just a small fraction of what Slack is doing.
there's also web-based chat apps that use next-to-no resources. If slack's webapp is so heavy, what makes you think a native app from the same company would be considerably better?
