This was something that confused me for the longest time, but it turns out those screens aren't what you think they are - the mission control consoles and the large projection screen back in the Apollo era weren't really computers in the modern sense of the word, but rather more align to television monitors that could be set to different channels. The images themselves were actually a composite of raw points plotted and rendered on a mainframe, then overlaid with physical slides containing the graphics that you're probably thinking as being similar to a GUI - all having to be preformatted for the different types of data the mainframe could display of course, with the combined image filmed with a video camera and essentially broadcast through closed circuit television. There was actually a complicated mechanical system in place that would pick from a large bank of slides when a person on one of the consoles requested different information.
So yeah, if the displays looked decades more advanced then anything that was possible at the time, it's because in reality it was more of an electromechanical system that appears way more advanced then it actually was. It was also mostly passive - other then requesting new data, users at the consoles couldn't really interact with the system like you would a computer, not in the way that movies tend to suggest. Again, imagine the consoles as being more like TVs with a set of closed circuit television channels broadcasting various data.
Source: https://arstechnica.com/science/2012/10/going-boldly-what-it-was-like-to-be-an-apollo-flight-controller/2/
As for the large screens, since they were back projected there's actually a large, blacked out projection room directly in front of the mission control room, apparently called the "Bat Cave", which is weird to think about. I wonder if they still use back projection for those screens?
