And let's not forget that even Layzner, a series coveted by western fans for being a "serious" mecha show, goes from being a fairly somber story of children trying to escape from an unstoppable threat to being like one of those Italian Mad Max knock-off post apocalyptic movies. Complete with ax-wielding thugs wearing giant wigs and hockey masks like Lord Humongous. And that's before the show gets into ancient alien space magic.
And sure, Macross blasted the Earth, but Gundam killed off half the human population in its opening narration. Space Battleship Yamato opened with the planet being a nuclear wasteland. Dancouga has Earth's military forces being squashed in a matter of minutes with fiery death. This is just an aspect of the genre. When people talk about the three pillars of Macross, they don't mention the wanton destruction because that isn't what made the series stand out. And as far as "seriousness" is concerned, ZZ Gundam starts off punk kids trying to steal a Gundam, yet eventually has very heavy situations involving things like colony drops and a deadly civil war between Neo Zeon factions. And this is while the show continued to have a 10 year-old physic girl be a major character. So I really don't see how battlefield idols is an impassible wall for Delta reaching the same levels of emotional resonance as any other Macross series (or anime in general).