Does Being Content Leads To Less Improvement?

The question, "Does being content with the way things are prevent people from improving themselves and doing better?" suggests that being content leads to less improvement. In other words, satisfaction brings about less productivity. In my opinion, by being discontent with the way things are, people are able to improve themselves and society all together. The evidence to support my viewpoint is pervasive.
An epitome of this situation can be seen in Martin Luther King Jr., a man with great hunger for an important thing lacking in society in the mid-1900's: African-American rights. Ever since he was a kid, he was always dissatisfied with the treatment of African-Americans in public places, like buses, restaurants, etc. Then came the Civil Rights Movement of the 1960's, in which he became motivated to be a part of to battle this injustice. Soon, he became a crucial leader of this movement, leading speeches and marches that captivated the nation. Without Martin Luther King Jr.'s dissatisfaction with society, he wouldn't be motivated to lead a campaign to freedom, proving that discontentment leads to improvement.
Henry Ford had an ambition to bring affordable cars for the masses to drive, but was always derided when he brought his idea to his colleagues. To the dismay of his colleagues, he managed to build a car for the masses, and was able to produced hundreds of thousands with his new assembly line manufacturing technique. By being content with the way that automobile transportation was available to only the wealthy, he would have never been spurred into making the car revolution that changed the foundation of American society