[Alberta's Child]

That's baloney.

They used to alternate between red and blue, and many years ago I remember networks having opposite color schemes in the same election year.

The 2000 election changed that, because the red/blue color scheme for that election stayed undecided for many weeks after Election Day and was a regular feature on nightly news reports. People just got used to it, so the networks kept it that way.

[ealgeone]

Before the 2000 presidential election, the traditional color-coding scheme was "Blue for Republican, Red for Democrat,"[5] in line with European associations (red is used for left-leaning parties).https://en.wikipedia.org/wiki/Red_states_and_blue_states#Table_by_year_since_1984

I believe El Rushbo as articulated this as well.