well that's the issue, isn't it?
the graphics options that we have are slow and complex, and they don't solve the problems like a terminal and therefore the terminal persist.
consider something like grep on multiple files. it should produce a list of lines found. the graphical terminal takes that list and displays it. it can distinguish the different components of that list, the filenames, the lines matched, the actual match, etc. because it can distinguish the elements, it can lay them out nicely. a column for the filenames, colors for the matched parts, counts, etc.
grep would not produce any graphics here, just semantic output that my imagined graphical terminal would be able to interpret and visualize.