Well, news fatigue is possibly a legitimate not to incrementally change the anthem.
Kinda reminds me of Linus Sebastian's (LTT/LMG/WanShow) take on a video game (Beat Saber) where he said he basically doesn't play this game anymore because every time he boots it up, it requires a small update that breaks compatibility for 3rd party mods.
If you make a small change every year, or 5 or whatever, people are all gonna be on different versions of the anthem, and it's gonna be sort of difficult to get everyone on the same page.