Great thread and answers. The reason it's non-traditional to invest in buy n holds vs 401k is because there are no 'got real estate' commercials but plenty of banks, brokerages and financial advisors marketing endlessly. They are the middle-men who stand to profit. No middle-man in REI, no media attention, and little-to-none mainstream news coverage.
Therefore, that makes it appealing to the masses who think and are led to believe it's the only way to exist in retirement.
The turning point for me to stop contributing the max of my own money to my poor 403b plan just happened this year (in the land of public education, we have to use the equivalent of a 401k called a 403k plan. These plans were just exposed in a 4 -part series by the New York Times in June by Tara Siegle Bernard about the excessive fees and expenses).
REI have known this for years and it's no secret: Your buy n holds generate income streams tax free potentially and you're left with an asset. Your Roth 401k/IRA is obtained with the same after-tax monies and passes tax free but you are not making passive income over the years, you have very limited options, and control.
From what I see, REI can offset income with RE expenses and thereby get the same if not better tax-saving benefits as with a deferred tax savings account.