Atom predated the LSP and leaned heavily into customizations with all the plugins running inside the UI thread (more like a traditional web page and 3p scripts). At the time they viewed the extreme customization support as a feature, and there was a thriving ecosystem of folks making plugins.
That architecture has a major flaw though. A default install was fast, but a real configuration with all the plugins ended up quite slow.
VSCode's architecture worked much better in real world configurations, and it turns out better performance wins in the editor space, even if it meant losing certain customizations (up to a limit). The architecture also allowed seamless remote editing, something Atom never could have done.
The interesting thing has always been that both were built on Electron. Atom's developers had built all the tools and primitives needed, they just didn't have the understanding of the long term ecosystem effects of their design.
That architecture has a major flaw though. A default install was fast, but a real configuration with all the plugins ended up quite slow.
VSCode's architecture worked much better in real world configurations, and it turns out better performance wins in the editor space, even if it meant losing certain customizations (up to a limit). The architecture also allowed seamless remote editing, something Atom never could have done.
The interesting thing has always been that both were built on Electron. Atom's developers had built all the tools and primitives needed, they just didn't have the understanding of the long term ecosystem effects of their design.