@ticky three of our biggest cities correlate super directly to time zones (NYC is eastern, Chicago is central, LA is pacific) and mountain time can use Denver which is still pretty easy to remember. It's 3 hours' difference from coast to coast which I was taught as a kid. I guess we're spoiled by having it be pretty simple? IDK.
I think there's also an argument that time by city is more useful because some of the time zones cut up really weird, but I get your frustration.