100k does not equal 100k
If you are self-employed or a W-2 employee, $100,000 of the money that you make, compared to $100,000 of the money made through rental income, is completely different. Rental income is more valuable than W2 because the investor gets to keep more of it! But don't just believe me, talk to a CPA who is familiar with real estate and how it gets taxed. (However, beware, not all CPAs were created equal. Make sure you are talking to one who really knows the real estate investing tax scene.)
This means a W-2 wage earner actually needs to make more money than a real estate investor, in order to be able to spend the same amount after taxes. It also means that you are most likely working away in an exhaustive exchange of your time for your employer's dollars. I do most of my work at the beginning of a real estate transaction - a lot goes into buying the right property, then setting up a property with proper renters at an appropriate rental amount, and ensuring all maintenance and management is in place properly. But then I pretty much move onto the next one. Every month that rental income comes in and adds to the cash in my bank account from other real estate income and I eagerly look for the next investment to put those funds into.
The point here is - as a self employed worker or an employee, you are working hard, paying more taxes, and probably not building up very much wealth - hoping to someday save up enough money, so that you won't have to work.
Obviously saving money does work for many people - but typically these are people in very high income brackets and are extremely disciplined. I definitely applaud these people and they do very well in retirement. But not everyone is a very high level income earner.
And also it is obvious that some self-employed people are able to create companies so large that they do, in fact, have something so valuable that they will never really need to worry about money. But this is a select few.
On the other hand, just average real estate investors can watch their rental income increase every time they add a new investment and think about how they will still have that stream of income in one month, one year, one decade, and even next century when they hand it all down to future generations. And they don’t pay a lot of taxes.