Yup, that’s basically it. It shows quite well in the red and blue voting maps after each election. Huge cities solid blue, the countryside solid red.
The generations may have much to do with it, but the cultural differences of city vs country produces leftists/conservatives in each generation beginning with the Depression/WWII crowd on up to the most recent generation.
If the “Greatest Generation” held firm reins in the 60’s, we would not be where we are today. They survived the worst, won the big war, then gave it all away.
Because of a high percentage of turn-over in residence, big cities and college towns are the easiest places to commit vote fraud. Voter lists have lots of "voters" who no longer live at the listed address; and local poll watchers cannot recognize the local voters.
Where do Democrats win elections?