Let's take a look at the various Republics out there to see which one has a better track record than ours. BTW that is what we live in not a democracy.
The next attempt at a Republican form of government was France. Since their republican revolution they have been through 4 different republics (they are on their fifth) and three different monarchies. That is eight different forms of government in 210 years. We are still on our first republican form of government.
The next experiment in a revolutionary republic was Haiti.
I have lost count of the number of governments Haiti has had. And let's not even compare the two economies.
So, why should be abandon the longest lasting republican form of government?