Neither of those games were that heavily watched (appx 1.5M each) and Texas had cratered long before they lost to BYU (11-15 in conference play in the 3 seasons before that first loss to BYU)*, so it was just more of the same in some ways.

That said, BYU also has some of the most vocal active fans online. Other fanbases might be larger, or more likely to watch games on TV, but BYU fans are the most engaged online fanbase I see.

Because of that it's often brought up by BYU fans and has now become something larger than it was.