It’s tremendously important to realize that Vim comes from a VERY long line of text processing utilities that stretches back over a half a century. Vim is the result of constant iteration on a set of design ideas and conventions that predates it. `Q` for `Quit` is one of the oldest Vim commands, tracing its roots all the way back to the `QED` editor of the 1960s[1]. Changing it now would be foolish.
While I love vim, your argument holds no water. By your argument, it's foolish to change anything at any time, because everything traces its roots back to "something."
[1] http://wayback.archive-it.org/all/20150203071645/http://cm.b...