Gonna need a citation on that. Every tab of Gmail I have open takes up more RAM than my fully-featured Outlook desktop app that's pushing an order of magnitude more items through Exchange.
Slack, Discord, and Teams are loads more heavyweight than all the fanciest (non-Electron) IRC clients. Or look at Telegram: wicked fast native client that's barely using more than 100 MBs on my box with 20 some odd group chats all pushing instant multimedia notifications every couple mins.
Not to mention all the Electron counterparts are just slower. I actually don't know what black magic Microsoft did to make VS Code so snappy (it's way more responsive than all those chat apps I listed above), but it's also still noticeably laggier than Sublime and true Vim.