Building wealth over time has less to do with your income levels or investment returns and more to do with your savings discipline. As Peter Lynch says,
"In the long run, it's not just how much money you make that will determine your future prosperity. It's how much of that money you put to work by saving it and investing it.". Wealth is the accumulated savings, over time, that is left over after you are done spending from your income. Because you can build wealth without a high income but have no chance without any savings, it is pretty obvious which one deserves a higher priority.
To me, money represents freedom and independence and not a means to engage in conspicuous consumption. Spending beyond a modest level of materialism is mostly a reflection of ones ego. One of the most effective ways to increase your savings is to raise not your income but your humility.