It has already happened , and there 2 rather huge commercial examples�
And those are not your everyday examples. Reaktor is THE modular audio synthesis environment , by far the most popular. With its close competitor being MAX/MSP.
Softimage on the other hand has been the dominant 3d app for 80s and 90s movies,but even for other 3d apps node setups are a must have. Though all 3d apps come with python APIs and python having a reputation of being very much liked by people new to coding, artist in both sides , music and 3d graphics prefer foremost node setups. For example Houdini a very popular 3d app has full integration with nodes , anything the user can make can be controlled by nodes.�
Generally speaking I am not a big fan of the infinite "cannot". There is no way to predict something unless you seriously try it. But in the end any problem can be overcome. Text based coding has prevailed because early computer could not handle graphics well. There is definitely a recent shift to more visual coding and I doubt that text code is doing anything else than slowly shrinking in significance. The way I see it, text coding has become less and less managable , visual coding offers really good alternative managing very complex structures being closely tied to the GUI. Not that text coding cannot do this, but people associating with it, tend to not be designers and you need designers to improve workflow at least on the user level.�
Languages also will play a less significant role seeing the appearance of more and more specialized tools like it has already happened in music and 3d industry.�