The Constitution starts to become a little like the Bible: Once a pretty good idea, born out of its time and back then a great set of rules to live by to ensure that everyone can survive and thrive.
It's just that times change, stuff gets invented and certain things ain't as simple as they used to be, while others got way simpler. Plus in both cases people who kept reading the stuff over and over trying hard to find loopholes and, of course, finding them to subvert the original idea.
In other words, rules and regulations have to keep up with time. Else they become a relic and a tool for mocking them.
Except that the US Constitution is based on a set of basic and nearly-timeless principles of human nature and how they interact with and within governments that have proved themselves over history spanning from biblical times until the 1700s when it was written.
Human nature and the nature of government corruption and politicians' lust for ever-more power & control have not changed since the 1700s.
There is already a process included in the Constitution for any necessary modifications. That's what the Amendment process is. It's slow and difficult, and requires an overwhelming majority of people to approve for good reason. If it can be changed by whatever short-term political winds that blow, then it become useless as a standard and/or as protection against government oppression of citizens.