It already exists, it's called pyproject.toml. It already existed for years in the form of setup.py. Requirements.txt means that projects can't be automatically installed which contributes massively to the difficulty of getting packages to work.
It may be a convention but in practice if you want to publish your package to Maven Central you need to prove ownership of your group ID domain. (Or ownership of your SCM account, which is in essence another domain).
I updated my system recently and KDE under X11 started stuttering all the time, especially when opening new windows (which made using IntelliJ unusable, for example). Switched to Wayland and it just works. That's all it really took for me to go from a "I don't care about Wayland" guy to "I am a Wayland truther" guy.
Similar story for Pipewire; Pulseaudio had crackles and Pipewire didn't. Such is the way of life.