You may also be interested in this wiki page about direct democracy. Notably, the framers of the US Constitution were very concerned about the tyranny of the majority. All the institutions and checks and balances in the system are there precisely because you can’t always trust large groups of people. Direct democracy is highly problematic, at least as much so as a system with intermediaries.

Direct democracy was not what the framers of the United States Constitution envisioned for the nation. They saw a danger in tyranny of the majority. As a result, they advocated a representative democracy in the form of a constitutional republic over a direct democracy. For example, James Madison, in Federalist No. 10, advocates a constitutional republic over direct democracy precisely to protect the individual from the will of the majority.