Earlier quoted context omitted.
how can you measure the performance difference between an app that exists and one that doesn't?
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.
[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.