Partially true. None of the mythologically-lionized founders were perfectly omnipotent and couldn't hope to have predicted changes in society, technology, economic development, or pervasive corruption. They also couldn't envision ignorant, craven, leaders of poor character being given immense power and ignoring traditions. It's bikeshedding whether a monocameral or bicameral legislature parts, executive, or judiciary is more important, because currently, all 3 are totally compromised in similar manners that cannot adequately be reformed from within in a reasonable timeframe. The problem is a small cabal of rich people and their enablers have corrupted it to the point where no lasting fairness or integrity can be restored and vigilantly assured. The token "clean money" elected officials are a drop in the bucket when 90% of their colleagues and their large benefactors are legalized and pardoned criminals whom deserve to be imprisoned.
It’s naive to hang on to this fantasy of a small cabal of rich people ruining everything. It’s not at all the case. No one is being tricked. The voters are the problem. Go and talk to them instead of putting them on a pedestal as tricked victims. They are rotten and that’s why they vote the way they do.
We have a moral disease that infects tens or hundreds of millions not some tiny number of ultra powerful parasites.