Indeed. Much of a modern Linux desktop e.g. runs inside one of multiple not very well optimized JS engines: Gnome uses JS for various desktop interactions, and all major desktops run a different JS engine as a different user to evaluate polkit authorizations (so exactly zero RAM could be shared between those engines, even if they were identical, which they aren't), and then half your interactions with GUI tools happens inside browser engines, either directly in a browser, or indirectly with Electron. (And typically, each Electron tool bundles their own slightly different version of Electron, so even if they all run under the same user, each is fully independent.)

Or you can ignore all that nonsense and run openbox and native tools.

A month with CrunchBang Plus Plus (which is a really nice distribution based on Openbox) and you'll appreciate how quick and well put together Openbox and text based config files are.

Which is baffling as to why they chose it - I remember there being memory leaks because GObject uses a reference counted model - cycles from GObject to JS then back were impossible to collect.

They did hack around this with heuristics, but they never did solve the issue.

They should've stuck with a reference counted scripting language like Lua, which has strong support for embedding.

COSMIC is gaining ground as a JS-free alternative to current desktops, so hopefully you won't be limited to openbox and such.