This. When the ground temps hover around 40F, the snow melts quite easily. Then the air temps get in the 20's and water refreezes on the road. The ice is much more dangerous than the snow. That's why we close schools, businesses, etc.
And it's not the dusting that we get annually. We can handle that. It's when we get 2-3 inches of precipitation that forms ice on our roads that makes it dangerous. We don't drive with bags of kitty litter in our trunks, or just whip out our chains when it gets dangerous. So we shut down. If its orchestrated well, it's a fun holiday we can all laugh about afterwards (See "The Snow" from San Antonio, 1985. If it's not orchestrated well, well...
We can all complain how people in other regions can't handle unconventional weather - Hurricanes in New York (don't build where it floods), 100F+ temps in the Midwest (install air conditioners), Snow in the deep south (buy more snowplows, chains, salt, sand, etc.) Yes, there are solutions that make the situations tenable. No, the capital investment for an event that happens every xx years isn't worth the financial losses from shutting down the city for the time it takes to deal with the situation.