I am not implying anything.
In this video, they clearly and honestly say why: the software is poorly designed and is difficult to maintain, and no team member is willing to maintain it. Now, 2 years later, it still has no maintainer. It is abandoned and remains in repositories AS IS.
If you have mate-menu package installed in 20.04, it will remain installed after upgrade to 22.04. It is not installed by default in fresh installations.