That was the case in the UK from 2010-2015. It's called a minority government.

Various factions horse trade until some coalition of parties has a majority, and then they rule as coalition. Members of both the Conservatives and Liberal-Democrats had cabinet seats.

The main downside to this sort of process is that sometimes negotiations take a long time. Belgium spent nearly two years bickering over forming their coalition in 2010.

> Sure, that works fine when one party has 50%. But what happens when no-one does?

Form a coalition that does or have new elections. You can even set a timeline after an election for a coalition to be in place or new elections are mandated by law.

That comment was literally about coalitions ...