You can never earn so little that you can't save anything.
On the other hand you can never earn so much to not be able to spend everything.
A person making a million dollars a month and spending a million and a dollar is a poor person.
You are only as wealthy as long as you can live without working.
See the above sayings? All of them imply that wealth is a function of income and frugality. And whether you believe it or not - self made wealthy people come in various packages: Shrewd and inethical, frugal and hard working, smart and risk-tolerant or any mix of those qualities.
Or to put it into a different perspective: Jesse Livermore explained difference between a speculator and an investor on a investor he knew.
This said investor went to see two company managers he was either holding stock of or thinking about buying it. Both were happy to present the guest with any information he wanted to see. The difference was that first manager wrote calculations on beautiful (expensive!) embroidered paper, which he would throw into thrash one by one mostly empty.
The other manager wrote calculations and numbers onto cut envelope paper. This manager supposedly ordered all the envelopes from the office be brought to him daily and the first thing he did in the morning was to cut all the envelopes into small sheets of paper and have them distributed throughout the office for taking notes.
The investor sold all his holdings in first company and increased them in the second. His decision payed off massively. His rationale being that wasteful attitude of the first manager and the frugal attitude of the second manager. Trickle down to the rest of the company. Thus influencing the way business operates.
Frugality is all about eliminating waste, tiny bits at a time. And in hierarchy the whole organization takes some of the character of its founder/leader. Thus one could infer that for a long term business success its founders/leaders absolutely must be frugal.