I hear what you are saying.
What seems unstable to you may actually be good for THEM. Shaking things up isn't always bad. Most important, their government shenanigans don't seem to affect the daily lives of anyone.
Germany's coalition government system works fine too, and they've had to go through the upheaval and expense of reunifying with Germans who lived 50 years under the destructiveness of communism.
Italy has had TWO Renaissances and has produced some of the finest, well, everything, this planet has ever seen. It's the most visited, tourist-wise, country in the world. Their upheaval type of government seems to work for them. It certainly doesn't ever seem to interrupt the flow of daily Italian life.
The British parliamentary system, of course, is rock solid. The only thing I find weird is the House of Lords. Who needs it?
As I've gotten older, I've become less critical of these coalition governments. I see how well they really do work but am glad not to have to be under that system.
I also have gotten very frustrated with OUR two-party system. They seem to be less and less TWO-PARTIES and more like ONE party smack in the middle, with all the power and money (Read that as TAXES).
Their fringes on either side, are like angry, spoiled children, screaming for change from their centrist parents.
Sigh. I've become such a cynic.
Yes we could gain a lot from coalitions and the emergence of 3rd parties that don't just diminish the chances of parties to win but instead enhance them. It's interesting that the Progressive party came in 2nd in 1912, and possibly something could have come of that if not for W.W.I.?