This ins't a common known fact, but the Chozo people were actually a highly organized drug chain.
Now you're probably wondering why, or thinking that I, Sir Kibble, has lost his mind, but think about it. Look at the similarity between the two
words.
-metROIDS
-steROIDS
It becomes obvious if you follow that on its logical route, you eventually end up with the conclusion that the Chozo actually engineered Metroids to act as a futuristic and more capable Steroid. Metroids are designed to drain energy, and they have the power to release this energy either by natural or conventional means like the Space Pirates were doing. After the Metroids would drain enough energy, the Chozo would harvest this energy and sell them around the Galaxy in the black market, making huge dividends and profits for their race. It's no wonder they had all the resoucres to create those neat weapons and battle armor. Because they were all crime lords!
The Space Pirates also discovered the wonder and marketing potential of this new living drug, so they stole them from the Chozo (Who eventually all died of liver posioning. Thats the real reason right there). In the past, the Space Pirates made a dangerous living of ransacking other freighter ships for goods to sell on the black market, but now that the Chozo were monopolizing the market, they had to steal them to protect their way of life.
The Chozo raised Samus to defeat the Space Pirates, because now the Space Pirates had stolen their market from them. The Chozo were so enraged that the Space Pirates had stolen their brainchild actually, that they raised Samus to destroy them also, and even the Metroids.
Why the Metroids you ask? Well, the Chozo could always make more Metroids, but they knew the Space Pirates couldn't. After Samus had caused considerable damage to their market, they tried to engineer their own Metroids, the Mochtroids. This however, was a failure. Then the SPace Pirates stumbled on another miracle drug, Phazon.
The Space Pirates also realized that this Phazon, if kept contained, had an even larger potential than the Metroids did. Now the Space Pirates had their answer for Samus, and for the Metroids.
The harvest of Phazon soon began afterwards. The Space Pirates searched the galaxy for Phazon, but wherever they went, Samus was sure to follow.
Samus is the only thing left of the once mighty Chozo Drug Empire, and the only thing left standing between the Space Pirates and succeeding in monopolizing the whole Galaxy.
Sum Up:
The Space Pirates and the Chozo: Their kinda like a mafia, a ring of crime lords battling to control the galaxies markets.
Mother Brain: Leader and head of the Space Pirates. The big cheese of the operation, the brains behind it all. (Hence Mother 'Brain')
Ridley: Mother Brains second-in-command. He does all of MB's bidding and dirty work, including destroying Samus Aran.
Metroids: The living drug. Used to harvest energy for the Chozo's Steroid market.
Samus Aran: Protector and justice bringer of the Chozo. Raised to destroy the Space Pirates and their market which they stole from the Chozo.
Phazon: The answer to the decrease in Metroids. Phazon has ten times the potential of the Metroids, if the Space Pirates can find a method to control it's spontaneous and severe side effects.
The Galactic Federation: The police of the Galaxy. The GF have been trying to stop the crime underworld of the Chozo and Space Pirates for decades. They've recently signed a contract with Samus Aran to do their bidding, for a high price.
And that sums it up. Everything else is a lie engineered by the Chozo.
