> More importantly though, the best way to climb the wealth ladder is to spend money according to your level.
As far as I (a non-economist) can personally tell, any notion of climbing up some abstract wealth ladder is synonym with a salary increase for the vast majority of people. Other methods, whether they involve quantity of free time or already-available money, are intrinsically tied to the quality of your job or, failing that, the quality of your parents' or partner's jobs.
Personal net worth, while definitely an important factor in this equation, is far less so than income in my opinion. A fiscally irresponsibly professional worker living from paycheck to paycheck has "grocery freedom" while a person with 10,000$ of accumulated wealth and no income whatsoever (let's say they are between jobs) is far more likely to buy the store brand margarine. Similarly, the former will most likely not achieve "travel freedom" without decades of hard work, of careful spending, of saving, investing, etc.
Simply put, no amount of "not carelessly booking flights" will turn you into Jay-Z, let alone into that small business owner across the street with the McMansion and the gaudy Christmas decorations. The undisputed "best way" to climb the wealth ladder is to receive large amounts of cash from some external source.