Well, Slack is currently taking almost 3 GB of memory on my machine. Not entirely sure if that's due to Electron or Slack, but I have never found an Electron app that didn't consume vast swathes of memory.
An empty Atom window containing 5 source code files consumes about 120MB of RAM. For comparison with native apps, an empty iTerm2 window uses 100MB, and so does an empty Notes.app window. The base memory footprint imposed by Chromium is not that significant.
Granted, it is totally normal to have packages when using Atom, but their memory cost shouldn't be considered a penalty that you pay due to Electron. Rather, it's a penalty that you pay if you want an extensible application in which extensions are allowed to use JavaScript.
When I run `atom --safe` it starts at around the same amount of memory usage: https://imgur.com/j4Co4n6.png
Side note: Running that command is now preventing my from quitting Atom using the Atom > Quit menu entry. I had to force quit it to get it to close.
I developed an application with Electron (+ Vue + Node) for an internal tool used by non-technical staff at my work and I don't have nearly the consumption as some other applications, but there is a lot less occurring on the renderer process than it appears with other applications.
I've added VSCode (with a large project), my application's usage (censored because it's proprietary, but it's a document-based application) and the worst memory offenders on my system (16GB 2015 MBP):
I've heard of other similar strategies-- but the best one seems to be to offload as much of the work to the main process or talk to a binary wrapped up in the application and do as little lifting with the renderer (the Chromium portion) as possible. My results have been alright so far.