when royal blue was the official color, i) there was not the push to wear school colors to the games nor ii) was there a merchandise marketing emphasis as there is today.
Were marketing efforts on royal blue pushed, I believe it would sell. I'm 64 and so am partial to royal; however, I have 5 married children. all of whom are avid BYU fans and they all likewise prefer royal so I don't believe it to be an age thing but rather the emphasis on wearing color to the games and increased marketing efforts.