Every agreement in this world is a product of negotiation. The more people involved, the more complex the negotiation and the greater the compromises made.
The Constitution of every country had to be written and ratified by many. They all had a stake in how the government would be run, and a fair amount of compromise was made in the ratification of every Constitution.
John Adams and Thomas Jefferson are both referred to as the founding fathers of the United States. When John Adams lost the election to Thomas Jefferson in 1800, he was on a train, on the way to Massachusetts, on the day of the inauguration. Adams thought Jefferson was going to ruin the country and could not bear to be in Philadelphia to hand over power.
There were real differences between the men who signed the American Constitution, and consequently, there would have been a lot of bargaining between them as well. These differences were settled based on the political exigencies of the times. While amendments have been introduced since, these amendments are very hard to pass.
This is a problem that afflicts all democracies. Almost every constitution in the world was written for a different time, and they are being adhered to decades, even centuries later and being treated almost like religious doctrine.
In the book Range, the author talks about simple problems and wicked problems. Chess is a simple problem; it has a limited rule set, although seemingly large, and as the game progresses, there are only so many moves that can be made. The stock market is wicked and hard to predict. A large number of players are capable of making a large number of moves based on information asymmetry.
Having an ossified constitution makes the game of politics simple. The permutations and combinations have been well understood, and it helps the cause of political operators who have figured out how to play the game. This leaves them even fewer incentives to amend or change it.
We update everything, all the time, sometimes completely. Then why not the constitution?
The difficulty in modifying the constitution leaves us in a place where we are being governed by the dead and their compromises.