I think that's a quirk of how this type of auction pricing works more than anything. If everything in the area is going for 20% over asking, then posting a listing for what you actually think it's going to go for will make it look 20% more expensive than comparable properties, so you may get less offers. So there's this strange feedback loop that happens in local pricing, magnifying the list vs sold price disparity.

Realtors are often encouraging sellers to list below market rate to encourage bidding wars. When you have to go through several of these before you can get into a house, it causes quite a frenzy in people. This isn't the norm across the country.

In other markets, realtors usually have clients list houses above market value with the expectation the sellers will come down.

my realtor was able to estimate the price better than Zillow, I feel like they need a better machine learning model to accommodate different markets. (Denver, SF and Ohio are very different places)

In my recent long home search period, I didn't trust Zillow's price estimates at all. But i used Zillow religiously because it's UI/UX is just so good, so much better than the competition, I could do a survey of what's out there easier and quicker, and find out more of what I wanted to know about interesting listings.

Zillow "zestimate" seems to be something they're known for, but I don't think it's actually their strength as a product.