It’s not that they aren’t powerful enough - they are Turing complete and so can compute anything computable. But text-based programming tools have many many many many helper tools that we’ve developed over decades. Text-based programming is also more information-dense on the screen so it’s easier to keep references up to different parts of the code. Finally - it’s just a matter of adaptation - the reason keys on your keyboard are in layout they are is because 100+ year old typewriters used to get stuck more often with different layouts. And since text-based programming is an industry standard - I doubt it’ll change anytime soon.