Sure you could use an algorithm to do this, but realistically how many houses actually get listed in any of the top 20 real estate markets on any given day in a price range/size that is suitable for renters. You could manually scan through all of them with a peon that gets paid $15-20 an hour. So really what they are selling is a promise that an algorithm can do it better so they can sell themselves for 100-300x of what they are actually worth
You're looking at GRM. How much does it cost you to buy vs. how much money can you make off of it. And if you're crawling the data, you aren't limited to the top 20 real estate markets; you're limited to anywhere you have sales and rental data. And if you're a REIT... well, look at the numbers. If you're sitting on seven billion dollars and are tasked with the mission of turning a profit by renting single family homes, you're well beyond manually scanning. And if you aren't Blackstone, you start looking at doing your search third-party.The initial public offering of Invitation Homes on Jan. 31 raised more than $1.5 billion. The single-family REIT founded by private equity firm Blackstone in 2012 immediately became the largest listed company in the sector with an equity market cap approaching $7 billion. It boasts a portfolio of nearly 50,000 rental homes spread from coast to coast in 13 markets ranging from Atlanta to Los Angeles to Minneapolis.