They did a great job at that. It has lasted 248 years. But they also gave us a framework for updating our constitution and government, and that has been sorely neglected for a long time. The founders were wise enough to recognize that the system would need to change as times changed. What they didn’t seem to anticipate is the insane tribalism created by technologies that weren’t even a dream at the time, and how that tribalism would grind our government to a halt.