Why does a lot of synth-based music end up sounding the same?

The Synthesizer is, in theory, an infinitely versatile Instrument when it comes to it's Timbre.

Yet most synth-based music falls into broadly similar categories, those usually being Ambient, overtly poppy and techno-esque with using mostly sawtooth waves.

Now I do readily admit that I could be wrong about that and there could be a lot more inventive music made with synthesizers that uses unusual Timbres. But I do feel like there is a certain expectation to sound the same, based on a couple of distinct influences.

What is, in your opinion, the most unique use of synthesizers in music?