They don't need to predict the actual sale price of every given property perfectly to make money. They need to be able to say that with 99% probability, we will

They don't need to predict the actual sale price of every given property perfectly to make money. They need to be able to say that with 99% probability, we will find at least one offer for this house >= 500,000. The errant buyer with loads of cash is free to come in and offer more. As long as they turn a sufficient profit at the 500,000 price point they should be set. In competitive markets, for people familiar with local dynamics, this is very much possible in a short-term time window. The question is doing this at scale in a fully automated way for a much longer time horizon. Zillow tried and failed.