Many people use full IDE's to do their work - JetBrains, VS, etc - which are dramatically more resource intensive than Atom.
e.g. live libclang-based code completion for Emacs: https://github.com/Sarcasm/irony-mode
I don't think that's a fair assessment given the what is now minimum expectations around syntax highlighting, syntax/grammar validation, autocomplete, etc. We're no longer dealing with "plain text".
My Visual Studio doesn't need 16 GB of ram... I have enough with 4 on Windows ;)