>>58789331Nintendo doesn't dictate how the Pokemon brand is managed, these are decisions made by Game Freak, TPC and TPCi.
We know from the leaks that GF decided against doing another vocal track, at least for the time being. Basically boiled down to "Celestial was popular, but it was popular independent of the game". In other words, GF payed top dollar to produce and market an American pop song, and that investment didn't translate to stronger sales of SV. Celestial was popular, but it was out of context. It wasn't popular as a Pokemon song, so it didn't benefit the brand.
Compare that to other recent music projects. In Japan, Project Voltage is a top-to-bottom branding effort. Songs about Pokemon, with sound effects from the games, and unique art for each track. Or the recent "World Championships" soundtrack, which is a little less on the nose, but still makes sure you know "this song is about Pokemon". If by some miracle one of those songs went viral or became a top single, there would be no way to remove it from that context.
Even though he's personally a fan, I doubt Ed's management and label would've ceded that kind of control to TPC. A similar situation prevents Weird Al from reissuing his Polkamon track, since it's jointly owned by TPC's "Vaporeon Music"
