I've also been impressed by the progress in Ladybird. One point though is that there is an incredibly long tail of work in the major browsers related to OS-spec

I've also been impressed by the progress in Ladybird. One point though is that there is an incredibly long tail of work in the major browsers related to OS-specific work, performance, browser-specific features, edge cases, legacy support, etc. I'm not saying Ladybird "needs to" have all this, just putting some of it into context. And it's no slight to the project either; they've managed to get a lot working with a paucity of person-hours.