1. You can buy stock on margin (50%) - not advocating this, just stating the facts.
2. Using leverage, you can lose all of your money in real estate (I won't explain as I am sure you understand the risks - foreclosure anyone?)
3. Contrary to your example, depending on your timing, you may not make any money on real estate, even your personal residence. I am the perfect example of that, despite living in some of the hottest real estate markets in the country over 30 years (SF Bay Area, NoVa, Utah County). Unfortunately my ownership period in all of these places was when the local real estate market was flat or declining. I have made ZERO from owning a house over 30 years due to moves I made for employment. I tell my friends when I move in to sell and rent, until I leave, then buy again. My CA house is worth 4X what I paid for it. My Utah house is about 2.5X. My Nova House is about 1.5. My current house, where I have lived 10 years, isn't worth much, if any more than what I bought it for...Very bad timing...

But, very, very nice timing on your 2009 purchase. I wish I had the Acorns to have done more purchasing in that window. I think you will agree that 2009-2017 and the historic returns achieved is probably not a reasonable expectation for a 2019 purchase...In addition, we are mostly talking about people paying a few extra hundred bucks on their mortgage versus an investment that requires a lot of expertise and a lot of capital to do it...

My expectation is that the small minds on here are going to rip you for using real numbers, but I can only say. Wow! Almost perfect timing (my guess is your exit will be also)! And congratulations! Oh, and if you want to do another project with carried interest, give me a ring.

I think there are other important differences between comparing a return on paying down your mortgage (investment risk free and passive) versus real estate (active, leveraged, investment risk), but I am not advocating anything.