In Nor. Calif where I live, it's not elevation but conditions that determine chain control. Sometimes it can snow fairly low, sometimes not. Most of the time the rules are strictly enforced. I recently had to go to town for a medical thingy and the ~ 1-hour drive home took well over 3 hours b/c a lot of people didn't think they needed to chain up and they somehow got around chain control. Made for a huge mess, we sat for well over an hour and then crawled along for miles.
Most of the time if you have 4WD with proper tires on all four, you don't need chains (but carry them). We had several inches of snow that time and by night, at home, at least 13 inches. We never spun a tire, including going up our steep little hill.
Some of the worst conditions I ever saw was decades ago in Missouri. An all-night ice storm covered everything in 1 to 3 inches of solid ice. It was an absolute disaster, many people who ventured out went off-roading.... unintentionally. I had a '71 Camaro with Michelins and a limited-slip diff and I got around safely, but very very slowly.