How and why are the members of the community in Louis Lowry's The Giver unable to make individual choices?

In The Giver, the members of the community have ceded all control to the elders, who are the rulers of the community.  This is apparently a choice that their ancestors made a very long time ago, according to the Giver, who says, 

Our people made that choice, the choice to go to Sameness. Before my time, before the previous time, back and back and back.... We gained control of many things. But we had to let go of others (Lowry 95). 

The Giver is speaking of Sameness, of course, and Sameness is the consequence of the elders having removed choices from the people.  As I imagine this, some external force or conditions caused these people to think that they would be more secure, peaceful, and productive a society if they gave up choices and allowed their rulers to tell them what to do.  This was a tradeoff, as the Giver notes.  There is clearly enough food and shelter in the community for everyone, as well as education and some amenities of life. The people have given up choice for these forms of security.  From the elders' perspective, it is far easier to control a community that has no choices. If everyone has the same housing, furniture, food, and clothing, there is nothing to argue about. There is a perception of equality that helps the elders rule effectively. The elders can observe everyone's skills and talents and choose a profession for each, which is a more efficient allocation of human resources. They can choose partners for the people based on some sort of compatibility, which makes each household run more smoothly. Some women are chosen to bear children because they can produce better physical specimens, while women who do not bear the children can use whatever skills they have more productively.  This community is, in essence, a dictatorship.  If people do not want to endure this, there is the threat of release, just as in any other dictatorship, in which people who do not follow the rules can be and are put to death.  All of these are choices that most societies allow people to make themselves, which is, of course, not necessarily efficient or peaceful.  A society is messy when people make their own choices, and this community has avoided that.  It is a bad bargain, though, as Jonas comes to understand during his time with the Giver.