Switzerland is ten times smaller than France, and in general the people who live there are far better off (GDP per capita is doubled between France and Switzerland ($90,000 vs $45,000)).

It's much easier to form a consensus when your constituents are all affluent. It's much easier to govern a small country than a big one.

Switzerland clearly works moderately well, but the barrier for success was far lower than for France.

> It's much easier to govern a small country than a big one.

Then what about making small countries? We could then federate the result. Let the small regions take care of what can be handled locally, and let the federation take care about the big stuff (army, foreign policy…).