SwordGuy, I think what OP is trying to look into is how much the role of high income plays in the pursuit of financial independence. High incomes are empirically related to privilege (I can point you to a post in another thread if you're interested in reading more), so that much is a given. The next step is to examine the relationship between high incomes and progress towards financial independence.
Reminds me of the federally funded study of stewardesses back in the 1960s or 1970s. After gobs of money spent, they discovered that stewardesses were shaped like women are. Some tall, some short, some slender, some not. Who would have ever suspected it?
Senator Proxmire gave that study a Golden Fleece Awards for being the stupidest usage of tax money that year. He's dead, so you're probably safe from winning one of those awards if you apply for federal funding.
I say that because, well, duh, it's absolutely dirt obvious that people who make way more than the median income can get to FI faster and easier if they choose to. Truly, that's not worthy of "a study". It's a given, like gravity.
Let's start with a number for purposes of illustration. I'll pick $40,000. That's not an arbitrary choice. Justin at RootOfGood.com lives on $40,000 with a paid off house, but he has a $10,000 vacation travel budget. So, can the multiple cruises for a family of 5 and the 9 week jaunts thru Europe for that same family of five, and add back in some rent, and we're back at $40,000.
Median family income is about $59,000. Toss out some taxes and we're talking about the ability to save $12,000 a year or more, or 20%. That, according to
https://www.mrmoneymustache.com/2012/01/13/the-shockingly-simple-math-behind-early-retirement/ gives us 37 years to FI, or age 59 for someone who enters the workforce at age 22.
Not super early, but earlier than most manage, and definitely more securely than most manage.
Of course, we're assuming that this family's income and expenses don't change other than keeping up with inflation. What about people who choose not to increase their spending when they get a new raise? Who choose to save and invest the new income instead of spend it on a fancy truck or fancy house? Suddenly, their savings rate would be increasing and the time to FI would drop. And, of course, once the kids are out on their own expenses drop even more, further speeding up the timeline to FI.
Equally obvious, if a household makes $100,000 instead of $60,000, and they live on the same $40,000, they can FI even quicker.
If they choose to spend more than $40,000 they won't get to FI as quickly. This is simple math. What is there to study?
Whether they are privileged or not, the math remains the same.
If you want to study whether the odds of getting (and keeping) a better paying job is affected by privilege, go for it. The answer is "yes", by the way. But it would be of use to determine "how much is it affected."
But once someone has achieved (and maintains) that income, the speed with which they reach FI is determined by how much they choose to spend and how much they choose to invest. That's just math.
Since High Earning folks who FI extra early open up jobs for more people, that actually helps the odds of more people benefitting from that same high paying job. After all, if someone gets a job and holds onto it for 40 years, no one else gets that job. If, instead, they FI in 10 years, and are replaced by another person who FIed in 10 years, etc., four people could have reached FI with the same job. So why is anyone bitching about this? Because that's the only motivation I see for doing this study. And since, in this example, our 10 year to FI person is donating 75% of the income they could have made by holding onto the job, why the hell is anyone interested in more opportunity for people looking for reasons to dump shit on them?
