Starting with this history:
2004 - Appimage packaging format introduced
2006 - WPF released
2007 - MS Office 2007 released - using CSD
2008 - Adobe Photoshop CS4 released - using CSD
2009 - QML released
2011 - Kivy released
2011 - Gnome Shell released
2013 - Telegram desktop released - using QML
2013 - Electron released
2013 - GTK added support for CSD
2014 - Snap packaging released
2015 - Flatpak packaing released
2015 - vscode released - using Electron
2016 - Skype switched to Windows UWP > CSD
2016 - Google released Fuchsia OS - using Flutter for system apps
2017 - Ubuntu switched to Gnome shell > CSD Heaven > no global menubar
2018 - Flutter released
2019 - Firefox using CSD by default
2020 - Ubuntu plans a new installer - using Flutter
2020 - Sony introduced Flutter based UI for embedded devices
- Using shared libraries are dead. Softwares will include all dependencies in one file. (#appimage, #flatpack, #apk, #exe/msi, #dmg)
- Global UI Widgets are dead. Back in Windows XP days, using things like GTK, QT, Win32 is so common but not anymore. Softwares will responsible for the whole UI and rendering. (#webbrowser #flutter #WPF #QML #SDL #CSD #Walyand)
- Say Goodbye to menubar (ah dear sexy global menubar), statusbar, themes
- Users have no such limitation for network to deal with less download and updates.
- Softwares think RAM is chocolate, eat them all.
- Users have more storage to store apps with all their stuff. - Users don't care about saving some megabytes by using shared libraries with versioning limitations!.
- Users expect simple UI with stunning transitions, thats not possible with old buddies like GTK,QT,...
For your next project. need less memory and processor consumption?
Yes: Use Flutter or QML or SDL
No: Use browser based solutions like PWA, Electron, Cordova, Capacitor, etc.