Where do you expect them to go?

Happy and less confused customers

I would be unhappy and more confused if the menu would be changed ;-)
We have the possibility to build our custom administrator menus if we want to.

No the problem is that Templates does not go to Templates but to Stiles, and Manage not going to Manage but to Install.
So solution is:
Rename Templates to Styles or Link Templates to Templates
And Rename Manage to Install or Link Manage to Manage.

Except that would create even more confusion.

Extensions > Templates takes you to the default view of com_templates (presently the "Styles" view), which just so happens to have a secondary view also named "Templates".

Extensions > Manage takes you to the default view of com_installer (presently the "Install" view), which just so happens to have a secondary view also named "Manage".

By your logic, Extensions > Language(s) should also be renamed because that link takes you to the "Installed" view even though there is also a "Languages" view.

Changing the base links has "bad idea" written all over it. And I dare say changing the text of those items is equally as bad.

I would not be in favour of this change at this point in the life of joomla 3 and it is not relevant for joomla 4

If you really want you can create your own admin menu with whatever links you want.

This does not make sense....... Joomla is very unlogical and inconsistent ux. Is Joomla 3 not supported at least 2 years + from now?

The base link Extensions > Manage points to the Extension Manager as an overall component. That default view right now is the Install view. To me, if you're going to replace this with Extensions > Install, then you might as well completely eliminate the second level dropdown menu with the links to the other views (because how does Extensions > Install > Install or Extensions > Install > Update Sites make sense (I'm installing an update site?)). If you change this link to go to the "Extensions: Manage" view instead of the default "Extensions: Install" view, it is a fundamental change in behavior that is going to introduce a lot of user confusion and complaints because a common link has been changed somewhat inexplicably after being the same for at least 6 years (off hand I don't remember how it was in 2.5 and frankly I don't care enough to look).

The same bit applies to the templates link.

Again, if you really feel like this is excessively problematic, you are free to customize your admin menu structure as you see fit. But from a core perspective, changing this menu after it has been set up the way it is for as long as it has would be change for the sake of change and not be a UX improvement.

So the error was done in the beginning and no one saw it and because no one saw you say it will not be fix?

Clearly it is an error in your eye but not in others or we would have had millions of requests for it to be changed.

Again, if you really feel like this is excessively problematic, you are free to customize your admin menu structure as you see fit. But from a core perspective, changing this menu after it has been set up the way it is for as long as it has would be change for the sake of change and not be a UX improvement.

Therefore I am closing this