I'm not familiar with OS internals, but i believe having a system-wide consistent design (whole haiku is a monorepo) would enable you to simplify a lot of stuff

I'm not familiar with OS internals, but i believe having a system-wide consistent design (whole haiku is a monorepo) would enable you to simplify a lot of stuff. Also, many modern distros and desktop environments are bloated: you either have a choice between a full-featured, resource-hungry desktop (Gnome/KDE) or an efficient minimalist window manager (i3/sway). I believe the same applies to different parts/layers of the system. Haiku doesn't have the same feature set (yet) as full-featured modern desktops and doesn't have to deal with dozens of compatibility layers, so maybe that's also part of the reason it fares better.