Could work, except Electron changes very often. Electron is like 10 years old at this point, with 1,512 releases listed on GitHub, meaning 12 releases per month (151 releases per year). Only applications who use the same version would be able to actually take advantage of this, so not sure how big impact it would have.
Instead, Tauri (Electron-like framework) does it like that by default, using whatever you have installed instead of shipping their own runtime. Might be interesting if you're looking for a sleeker version of Electron (but made with Rust instead of mostly C++ and TypeScript).
Electron's release cycle is highly impacted by Chromium's release cycle because of how tightly coupled it is, so unfortunately this feels unlikely to happen.
A lot of Electron applications in the Arch Linux package repositories use a system electron package, it's nice. They have to be split by major version, though.