It’s also monstrously difficult to amend the constitution. There’s a couple of ways to do it, but either way, you need a 3/4 majority of states to approve an amendment (and the “typical” process also takes a 2/3 majority of both the House and the Senate). That was one thing when it was the 13 states colonies of New England, all of whom have relatively similar cultures if not socioeconomic needs but nowadays I have a hard time coming up with much that 38 of the states will agree on. As the US has expanded, states have very different circumstances with populations that prioritize issues very differently.
One could argue this is one of its problems. The average lifespan of any nation’s constitution is 17 years since 1789. I think if we can consistently update it as time goes on we would be okay, but as you said it needs a serious overhaul and I’m fearful that it is almost impossible to do at times. Sometimes I wonder if the US should rewrite its constitution I think it would be a smart move. Except I don’t know how we could possibly get a group of people to agree to anything even close to what we have now. The 2nd Amendment is a hot topic of debate as is. We argue it all the time. Plus if it conflicts any existing state constitution you run into more problems. Its somewhat like going to the dentist. If you go every few years you’re alright. Wait 244 years and its gonna hurt.