Small Percentage Representation leads to Unstable Governments

In the past I have spoken of the way other countries award Legislative seats (like our Congress) by portion of total vote. This is used in much of Europe and much of the world. The key to successful use of this system seems to me to be twofold. One pillar of success seems to be a fairly unified country - at least in political goals.

The other  pillar for4 successful use seems to be a threshold of vote percentage to be admitted to the legislature is at least of 5%. That means to gain a congressional-like seat, the party must have won at least 5% of the vote. This is the norm for the countries in Europe.

Then there are outliers - countries where a lower percentage of the vote is used in the legislative make up.. This use allows more parties and people to participate, particularly in places where the population is made up of different experiences and desired outcomes.

In these three western countries a lower percentage that seem to cause problems.

Israel: They are having their 3rd election in 5 years (and this includes a total of 12 months without a government being approved). Israel's threshold is 3.25% of the vote for a seat. There are multiple conservative parties, each various shades of "right wing" needs with very small parties. Holding them in coalition so the government doesn't fall is mess because there are so many parties, that a coalition usually only governs with a 1 or 2 person majority, meaning that any one party can collapse the government when they don't like a proposed law. Israel has had 36 governments since 1967.

Italy: Their threshold is 3%. Italians are economically divided between North, South and Rome. They are politically divided between Populists, Capitalists, Independence believers and (historically) Communists. Since 1945 they have had 69 governments, averaging one every 13 months.

Spain: The threshold in Spain is 4%. The governments are less volatile in Spain because Franco's dictatorship was fresh in people's minds for a long time. Spain also might have had in mind the many districts that are unique (for example - ATM's had to have all the 6 official languages in Spain - Castilian (Spanish), Catalan, Galician, Basque, Valencian and Aranese). The memory of Franco did, for a long time, make the government more united.