I disagree with the premise that desiring material things makes one happy and that those who seek happiness in other ways are somehow lacking or are victims or are not motivated or envy the rich. I am in the upper working class, have all I need and am quite content. I work hard every day as a very self-motivated self-employed freelancer.
What makes one person fulfilled is not necessarily what another one would desire. I could care less about fancy cars for example, but others love them. I am not "envious" of people who have sports cars - because my 2005 Nissan Sentra satisfies me.
I grew up in a poor, working class family and I never envied people who had brand name clothing and exceptionally large houses. I always saw that as wasteful honestly - but to each their own.
Assuming people who are comfortable with what they have are somehow seething with envy is not a correct assumption. There are plenty of people capable of experiencing joy in life without the need for materialism.
In fact, I think many people who fall into the trap of believing having more "stuff" makes you happy end up lonely, miserable and unfulfilled because they don't find what they need within themselves that is fulfilling. "Stuff" can never provide deep, lasting joy for life - it is fleeting at best, making people need more and more "fixes"
I choose happiness over materialism and if I never get wealthy I'm perfectly happy with that. I pay my bills and provide for my kids - and I pursue my own happiness on my own terms. There's no amount of material excess that would ever replace the joy my simple lifestyle gives me. To each their own.