[brianpaul]

I think there's kind of two aspects to that (why client/server):

1. The X protocol was roughly like an evolution of the VT-like protocols which were used for text-based terminals back in the day. Those protocols supported cursor control, simple character-based graphics, and later, simple vector graphics. X was an evolution of that to deal with bitmapped displays, mice, etc.

2. Hardware was pretty expensive. Giving everyone in the office an X terminal was far cheaper than giving everyone a workstation. Again, that was an evolution of VT terminals vs. minicomputers.

Even X terminals weren't cheap. In the early 90's a monochrome 15" terminal could be a couple thousand dollars while the workstation was at least 10x more.