The good folks at Electoral-Vote.com have published an interesting map of the electoral votes in the 1976 and 2020 elections:

As they say:

Compare the 1976 map with the 2020 map. Eleven states (including D.C.) stayed blue (D.C., Delaware, Georgia, Hawaii, Maryland, Massachusetts, Minnesota, New York, Pennsylvania, Rhode Island, and Wisconsin). Twelve states stayed red (Alaska, Idaho, Indiana, Iowa, Kansas, Montana, Nebraska, North Dakota, Oklahoma, South Dakota, Utah, and Wyoming). Twenty-eight states flipped (Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Illinois, Kentucky, Louisiana, Maine, Michigan, Mississippi, Missouri, Nevada, New Hampshire, New Jersey, New Mexico, North Carolina, Ohio, Oregon, South Carolina, Tennessee, Texas, Vermont, Virginia, Washington, and West Virginia).

In 1976, the Democrats won five states west of the Mississippi (Minnesota, Missouri, Arkansas, Louisiana, and Texas). In 2020, of these they won only Minnesota, but they picked up seven other states in the West. And the South was solid for the Democrats in 1976, except for Virginia. That flipped completely in 2020, except for Carter’s home state of Georgia. Stuff changes.

More than just the flipping between Democratic and Republican victories in each state, take note of the number of electoral votes that states either lost or gained. Pennsylvania lost seven while Florida gained twelve. New York lost eleven while Texas gained twelve. Illinois lost six and California gained ten. 

The population has definitely been shifting. Stuff changes indeed.