I always enjoyed reading this thread, watching the clash of philosophies play back and forth. Recently, I read a book that resonated with me and reminded me of this discussion.
"The Millionaire Next Door" is often quoted on this forum and is relevant to many Mustachians. It describes a type of millionaire who achieved his/her millions through aggressive savings, living below their means, but not necessarily having a high income. Although many MND-types have high incomes, many more achieved their wealth through frugality alone.
I recently read one of Dr. Stanley's later books, updated around 2009, "Stop Acting Rich ...And Start Living Like a Real Millionaire." In it, he splits the millionaires he profiles into "glittering rich" and "frugal rich." In the earlier book, he had lumped most of the glittering rich (those with assets who visible spend them on status badges) into inherited wealth or celebrities. In the later book he more closely examined glittering rich who had accumulated their wealth on their own. This was achieved by focusing on very high incomes, not frugality.
Both the self-made glittering rich and the frugal rich had one thing in common -- they lived within their means. The self-made glittering rich person did not spend their money on the expensive toys and high status items until AFTER they became wealthy. They had higher incomes and generally achieved their wealth at an earlier age. They were frugal compared to the general population until they succeeded, then had no problems spending their wealth within their means. (But their means are considerable compared to that general population.) Glittering rich requires a higher realized income to support the higher spending level. It also requires achieving a higher net worth to support that income.
Most aspirationals (almost everyone you know who has a luxury car or mini-mansion but is not wealthy) think that looking successful is the same as being successful. Only the glittering rich type of rich are visible to the public. Frugal rich (traditional MND-types) are indistinguishable from the general population. That's why people equate status spending with rich people.
There are many paths to financial independence. The OP's original question was why the focus on frugality on this site. It's because it works, and is a legitimate path for many people. It's also a key part of the philosophy MMM espouses. While having a high savings rate is difficult or impossible for some people, it is easier to achieve for most people than a high income. We don't live in Lake Woebegone, where everyone can be above average. You can achieve frugal rich with fewer funds as well, because a lower net worth is required to support a frugal lifestyle.
As for the lack of focus on improving investment performance -- I disagree that there is a lack of focus there. I have seen lots of discussion on using a passive approach to investments using indexing, there's a whole different subject forum for real estate investing, there have been people who are aggressively investing in individual stocks, and there is a very active thread on dual momentum strategies. Having a high savings rate will offset the need for high returns, but having high returns will reduce the amount of money you need to accumulate to achieve FI.
In "Stop Acting Rich," Dr. Stanley points out that there are many more frugal rich than there are self-made glittering rich. Of course, there are many, many more aspirational rich, who spend their money on status badges to "look rich" but never achieve much wealth.
This thread is just an example of a clash between these two paths to financial independence. Neither is wrong, and they both work. But if you give a frugal rich person a super-high income, all they will do is achieve FIRE faster. Example: Alfred Morris
http://gamedayr.com/lifestyle/athletes-2/alfred-morris-1991-mazda-626/I'd love to acquire the skills that you have to generate income, but I'm also naturally a fairly frugal person. Once my income goes over a certain amount, I don't feel the need to spend more. It's just not important to me. I also enjoy squeezing a buck. Even if I don't have to.