When was the last time when serious new instrument was invented ?

The wish to interact is very 'material', that's, substantial.

I will take a look at Tom Waits' arrangements.

The Therman and the Melotron come to mind as newer instruments.

The electric guitar of all things. Invented in 1932. It’s based on an acoustic guitar, but it’s a completely different instrument.

Electric guitar is so important, it can do many things, even sing almost like a violin.

Trey Gunn used a Warr Guitar.  It will play bass, guitar and can sound like a synthesizer.  Chapman Stick is another example.  Tony Levin is a master playing that.