That was 12 years ago. Are you complaining that Emacs got sane window management "only" twelve years ago? Please don't ever get into Node.js ecosystem, the pace of accretion would make you cry, standing in the shower, rocking back and forth.
Buddy I started using Emacs at version 1.8, and no display-buffer-alist is not "sane". Just maintaining a stable window arrangement in the frame is not something easily possible.
I'm not sure what you exactly talking about, I'm having hard time separating "facts" from "personal opinion" here. I'm not sure what you mean by "stable window arrangement" to be honest. As a practical example I can only think of "jumping between places" feature, where If I, for example to have multiple windows and tabs open in the same Emacs frame (well technically speaking, tabs kinda make separate pseudo frames, but anyway), I currently don't have good mechanism of finding "the place", there's no good way to build "the breadcrumbs path" where you can traverse through all the places visited, Emacs afaik doesn't have good mechanism of finding exact tab/window/buffer/location, I don't know how much of it is related to your idea of "stable window arrangement".
Overall, I'm personally happy with Emacs window management, it's highly customizable and extensible, it gives you powerful keyboard-centric control, it supports complex layouts, it is deeply integrated within Emacs' vast ecosystem. There are packages like ace-window, winum, winner-mode, golden-ratio, shackle, popwin, eyebrowse, perspective, window-purpose, etc. I don't know what you're complaining about, I guess because I have not seen something even better than that.