Page performance from sites made with WP's block editor is pretty good compared to other editor plugins too, which probably matters more than editor performance (more people generally read a site than write it): https://wptavern.com/gutenbergs-faster-performance-is-erodin...
I don't think it's fair to say the core team isn't doing much to improve or prevent degrading performance — they performance-test every PR: https://developer.wordpress.org/block-editor/contributors/co...
There's also a performance team (for general WP performance, but also covering the editor/JS) that meets regularly and posts minutes. https://make.wordpress.org/core/2022/02/01/performance-team-...
Page performance from sites made with WP's block editor is pretty good compared to other editor plugins too, which probably matters more than editor performance (more people generally read a site than write it): https://wptavern.com/gutenbergs-faster-performance-is-erodin...