Here is an example for you Yyz717,
The US is not a Communist country, but why? Because the majority of the people do not want communism. They want to be ruled under indirect democracy. Which is why the US is a democratic country.
If all of a sudden (this will never happen of course, at least I hope not) the people want to be ruled under communism and abolish democracy, then that is what the will happen to the US. It will become a Communist Country.
Same goes for Saudi Arabia. The people want to be ruled under a monarchy and maintain there old traditions. This is why it isn't changing.
Also, the Royal Family does not have its final say. Like democratic countries there is Checks and Balances.
The Royal Family has cabinet members who help them with there decisions and inform them what's going on. And of course there are government officials who check the Royal Family and make sure they do not abuse there power. There are different divisions of the government responsible for different roles such as the economy, health, etc.
So it is basically a modernized monarchy upholding the old traditions and beliefs.
Similar to UK's government.
It's not like the old monarchies of the medieval ages.
"Generosity is giving more than you can, and pride is taking less than you need." - Khalil Gibran