Yes of course it can vary, but if you live in salt lake city, you're scoring pow regularly every single year. If you MUST ski 7 days a week, all winter long then yes you can run into less than perfect conditions.
It's all about averages. What is alta's worse snow year? 275 inches? So almost double the snowfall of mount snow on it's worse year? lol
Sure. odds are better. Kirkwood averages about the same, 500 inches. It's good skiing, sits higher, gets deeper drier snow than the rest of the Sierra. The last real powder day at Kirkwood was in December of 2012. Averages don't mean shit to the family that flies in one week a year from Virginia.