YES, they were correct 250 years ago, but times have changed.
indeed, in certain matters, they have. but in important big picture matters, they haven't.
One thing that has remained constant is that if you are really serious about trying to govern, say, 300 million people as a single nation, when they literally have none of the traditional factors in common (race, ethnicity, language, geographic isolation, religion, etc.) that have tended to hold nations together over history, there are two basic ways to do it: force and moderate consensus. And assuming you don't like the former, it's actually very important to design your governmental structures in a way that will promote the latter.
Now again, they weren't always right in all of the structural choices they made in that respect, but they were right more often than they were wrong, and certainly so in putting us more on a republican, rather than democratic, path. And, as I've noted in the past several weeks' scotus threads, if you set aside the substantive questions underlying the various disputes that people on message boards seem to get most worked up about, a common theme emerges. It is that only by insisting that key social choices be made by the most democratically accountable representatives can we create the pressure for moderate consensus.
So sure, it's easy for modern people to dislike a bunch of old dead white planters and merchants who had the means to spend time to think, but they did do one remarkable thing that nobody had ever done before, and which has stood for a couple of centuries: they established good government through reflection and choice, rather than by accident and force. Which, to paraphrase Cal Naughton Jr., is a pretty good thing - and well worth honoring.