However, the last time I looked into this matter, GNUstep still has quite a way to catch up to macOS Mojave's version of Cocoa. At the risk of going off topic, I still don't understand why GNUstep never seemed to have reached critical mass despite all these years of development. I was just a kid during the mid-1990s, but KDE and GNOME took off around this time while GNUstep kept pressing on. Here's my thoughts: maybe in 1995 and 1996 the OpenStep API might not have been attractive to developers in a world where Windows completely dominated the desktop, but this doesn't explain the decision of the KDE developers to use Qt instead of GNUstep (as well as the decision of the GNOME developers to use GTK+). There may have also been much uncertainty in 1997 following Apple's purchase of NeXT about the future of OpenStep. Such anxieties would be alleviated sometime during 2001-2003 when Mac OS X was released and started gaining popularity, but by then KDE and GNOME (and their respective underlying GUI toolkits) were firmly established in the Linux desktop ecosystem, and to this day they remain the dominant Linux desktops, and many less popular desktops still rely on Qt or GTK.