It depends on the circumstances of the sellers/buyers & of the houses being sold, but I think things are changing.
When we bought our first house in 1997, the only appliances that came w/ the house were the stove & dishwasher. We wouldn't even have thought to have asked for the refrigerator. We were renting at the time, & I remember DH finding a used fridge to buy so that we'd have a fridge for our new house.
When we sold that house in 2003, the buyers asked us to leave the fridge, but we declined because the sellers of the house we were buying were taking their fridge. They still purchased our house even though we were taking our fridge (& washer & dryer).
I thought that fridges & washers & dryers always went w/ you when you moved! LOL!
However, my niece bought a house about 6 months ago that had been flipped, & all the appliances (including fridge & washer/dryer) were included w/ the house. Actually, most of the houses she looked at included all the appliances, I think, but she was looking at starter/flipped homes. My inlaws purchased a new house this past spring, & the fridge was included. However, in that case, the owner of the house had passed away, & her children were selling the house.
When we were appliance shopping this past week, a few of the salesmen asked us how long we planned to stay in our current house & urged us to keep that in mind as we considered which fridge to buy. Again, leaving your fridge when you move is new to me, but, apparently, it's becoming quite common.