how does no one recognize the theme for this movie?

This film has one of the best Superman themes ever composed, yet no one seems to ever recognize or acknowledge it. It's so good, that DEATH BATTLE! even used it for their Superman vs. Goku episode but even then, people only recognize the Dragonball theme that was used in tandem with this to create an all-new theme, but not this as a singular track. What gives?

I get that this isn't a super famous movie or anything, but you'd think someone would point out by now where half of that DEATH BATTLE! theme came from, yet no one ever does. It's such a shame, as the two melodies compliment each other perfectly, creating an all-new classic theme in its own right.

Here's the theme on its own:

https://www.youtube.com/watch?v=2HrFrAspWF8

Here's the theme mixed with the Dragonball Z theme:

https://www.youtube.com/watch?v=USWONQl6f7Y