> I'm not sure if I'd count a person who can buy enough investment properties
Enough means "1 or 2". So yes, many average people can.
They'll often put, say, $50K down and that's it.
Here's how it works.[1] Homeowner has a house that has some significant flaw that's so bad no bank will mortgage it. This means the homeowner cannot sell via traditional methods. It will cost, say, $100K to repair the house and bring it up to market standards, but homeowner doesn't want to spend the money. He may already be ready to move (this may be a second house - or an inherited house, etc).
His only option is to sell for cash. The house is currently worth $250K, but market rates are $450K.
Wealthy non-RE investors won't buy his house - they want a house ready to move in to.
So what does the "average person like you" do? He gets a hard money loan. A private lender gives him $300K. $250K is to buy the house, and $50K is to help with the repairs. The average guy also puts in $50K of his own. At the end of 6 months, the house is all fixed up, and now worth $450K. He sells the house, and pays back the loan, and makes a decent profit.
Alternatively, he gets a mortgage on the house, pays back the private lender, and rents the house out.
What's in it for the lender? A very high interest rate. Back when mortgage rates were 4%, private lenders charged 12%. While this sounds scary high, the average guy plans to be done with everything in 6 months, so it's only 6 months of high interest.
What's in it for the "average guy"? Well, he just got a house, right? Also, what happens if things go south (e.g. runs out of money because he misestimated repair costs)? He loses the interest and his $50K, and that's it. The private lender gets ownership of the house, but cannot go after his assets.
So if you can save up $50K, you can get a house. The real hard work is to identify the right property (i.e. one that can't be sold easily).
Everyone I know who's done this earns less than a SW engineer. Some people are blue collar workers.
Another model: The homeowner is in a bad financial situation and has not have been paying property taxes. Now the county is threatening to take away his house because he owes $20K in taxes. There are only a few weeks left for the deadline.
The investor contacts the owner and says "Hey, let me pay the $20K you owe, and sell me the house for $30K. If you can sell the house for more to someone else, go for it. But if not, here's my number."
If the owner could have sold it for higher, he likely would have already. Both ways he's losing the house, but this way he gets money.
Again, such properties are hard to find.
[1] This is just one model. There are others.