An infinite canvas Brainstorming Chat interface. Seriously, why is this not a thing??

This probably has been discussed and likely prototyped but why is this not a thing among chat interfaces?

PNG Preview(not fully zoomable)

Processing img f4n1ysqvxnlg1...

SVG full scale(open in an SVG viewer): https://drive.google.com/file/d/1W9iIzUlWhtmJoqmm8VVfynku7BJo8Xc3/view?usp=sharing