I don't think all the interesting stuff has been written. But more importantly, I think a lot of the existing software is just terrible. Big old monsters that can be time consuming to learn, and which kinda lock you in for numerous reasons. Horribly inefficient cluttered user interfaces, with old paradigms that aren't necessarily a great way to interact with the computer... I think there's a lot of innovation to be m…
> Money? That's harder, unfortunately. It's hard to innovate when people want to cling on to what they already know. This is a core element of my questions that other answers are unfortunately not addressing. Even if you make software that's less clunky than legacy-grade Adobe Kamatsu-tractor like offerings, how do you make make switching lucrative to the point of achieving self-sustainability?
Take Sketch for example (http://www.sketchapp.com). Everyone on our team used to use Adobe Illustrator, and now everyone uses Sketch instead, because for what we do, it is simpler and better.