The problem there isn't necessarily development, but rather the data accessible to developers.
What you need to have that level of visual interaction is the original stems (or something which emulates them relatively closely).
Services like https://www.lalal.ai/ are a step in the right direction, and will probably lead to what you--and many of us--crave. But as it is now, they require way too much computing to provide meaningful enough data fast enough to build a real-time visualiser.
But even then there is the whole issue of copyright which would bottleneck development even further...
What you need to have that level of visual interaction is the original stems (or something which emulates them relatively closely).
Services like https://www.lalal.ai/ are a step in the right direction, and will probably lead to what you--and many of us--crave. But as it is now, they require way too much computing to provide meaningful enough data fast enough to build a real-time visualiser.
But even then there is the whole issue of copyright which would bottleneck development even further...