Even though I made the most money investing in real estate, it still depends vastly on your choice of purchases.
The 160 acres of land in the Ozark National Forest that I inherited in 1975 was worth $200 and acre then and is only worth about $900 an acre now.
All my other investments did much better than this.
I do know people who lost money in real estate simply because they were not knowledgeable enough to know what they were doing and would frequently buy the best, most expensive home in the area and expect it to appreciate.
I always buy the cheapest home in a good area knowing that the more expensive surrounding homes will pull up it's value.