I guess it depends on how much of Qt you need. If you just need the basics you can import mainly what you need[0]. In the case of D though one of it's focuses is to work well with C++ directly. I'm not talking about maintaining it all, I'm talking about embedding it directly into the standard library of a programming language.

I guess you do make a fair point in regards to the LGPL though.

[0]: Here's an example of someone building only a minimal amount of Qt: https://github.com/dirtycold/qt-minimal-build