Material items don't make a better life, I know many people who have a lot of things, big houses and all, who are no happier than me. I'm not saying material items are bad, they can enhance life greatly, only that, as you say, a person can be happy and content without all those things.
Like you have pointed out, it's best to think about and be grateful for what one has, to find enjoyment and happiness...from that position it's easier to find improvement where required.
Yeah I agree, material items aren't bad for sure. I do know of friends who see these stuff as motivation to work harder in their careers, and that's their lifestyle choice.