One of the reasons is to be able to divide the votes, The Netherlands for example is horribly fractured. It currently has 15 parties and during the election there were 28 competing.
If your idea of a 10 man parliament would come in then less then half of the current parties would be part of the parliament. With about 1/3 of the votes disappearing in the trash can. Besides that people often want somebody from their own area to be part of the parliament. If in the Netherlands all parliament members were native South-Holland and none from the other 11 provinces you will start having issues with proper representation. This is because even in a country as small as mine the differences are massive between the provinces.
Another idea of this "by the numbers" approach is that the more members parliament has the less chance there is of them all being corrupted/bribed. That's why you will mostly see parliaments in the 10's in nations where the corruption is high (or where the population is low).
Further, with 300+ members of parliament, if every one of them were given a chance to speak, even if they only spoke for five minutes, it would still take >1500 minutes (= 25 hours!) to complete.
Most people usually don't even speak in the parliament, they are just there to vote while a more silver-tongued member of the party speaks on behalf of its entire party. When it comes to part
Edit: The Following concerns info about the comment Itamar Mushkin made.
The Netherlands has 150 seats so a government has to be formed by a coalition of parties having a total of 76+ seats. The current polls have the following outcome:
- VVD 20
- PVV 19
- PvdA 18
- FvD 16
- CDA 14
- D66 13
- Gl 12
- SP 9
- 50+ 9
- PvdD 6
- CU 6
- DENK 3
So the 4 largest parties and 1 other random party is needed to form the coalition, now here are the problems.
- PVV and FvD don't want to form a coalition with the VVD due to them
being pro-EU and having made budget cuts on healthcare. (Also some bad history there)
- PvdA, D66, GL and PvdD don't want to form a coalition with PVV or FvD
because they are considering them "Right wing Extremists". And they are also not keen on forming one with the VVD.
- SGP only finds support from CU and CDA due to them being conservative Christians.
- And Nobody wants to work with DENK because they can barely be called a Dutch party due to them openly supporting foreign governments over the Dutch one.
So the most realistic possibility would be VVD, PvdA, CDA, D66 and GL but we already currently have such a government and it is failing. (Massive protests and an approval rating in the low 30's)
Namely a broad coalition, with our current one being VVD, CDA, CU and D66 who had 76 seats together but according to current polls only have 53 (almost a 1/3 loss). This is because they had to make concessions due to their differences.
A few examples:
- D66 supports euthanasia, CU and CDA are Christian parties that see
that as suicide (and therefor a sin).
- D66 wants to take in more refugees and pay more towards the EU, VVD which is an economic party wants the opposite.
- D66 is more open to Islam while the other 3 are not.
And the list goes on like this for a while, and you could say that D66 is the problem here (which is true) but the point is that the other parties weren't large enough, have bad blood with the VVD or are even more left wing then the D66.
Until a coalition is formed our government works chaotic and can even lead to new elections with probably similar results.
And on a side note, VVD is called a party killer. Every party that ever formed a coalition with them had massive losses the next election. This is because VVD (although they are declining rapidly now) has been one of the biggest the last few elections forcing it's coalition partners to make decisions that are unpopular with their voters.