> If you're the President and Parliament is against you and you don't want to quit you have to step aside as happened in 1986, 1993, and 1997 and the system does become essentially parliamentary.

For a cohabitation to happen, you still need a majority. The legislatures in '86, '93 and '97 all had clear majorities. The current situation doesn't have it. Also cohabitation is likely a thing of the past since the constitutional reform of 2000.

> not parliamentary vs Presidential systems per se.

The system and the chronology of elections it creates has an impact on political strategies and the willingness to compromise.

> Countries that have a "culture" of coalitions

Countries that have a "culture" of coalitions have it because making coalitions isn't punished by the electoral system. France had a "culture" of coalition before the rules were changed. In fact, that "culture" is not some hard-to-pin virtue, it's political agents understanding the rules of the game, and optimizing their chances to win.

> You enter a coalition only when you have to.

Here is the thing: you never "have to" enter a coalition, and if you do so, you get milked by the senior party, because having the president on their side gives them an overwhelming edge. And so, at the next elections, you get destroyed because you've pushed little of your program and enabled the other side. It's much more rewarding to stay in the opposition.