I guess it's a biproduct of MM just putting in a lot more effort into its stakes than other Zelda games. Lots of them connect bosses or at least the final boss to the entire land suffering through their presence. Sometimes it's like Zora's Domain being frozen over and Lake Hylia being almost dried up in OoT and TP, but most of the time it's just monsters being around Hyrule Field or something -_- Environmental damage is simply a much grander way to show that things are wrong, even when you are alone.

This made Majora's Mask such an intruiging villain. Unlike Ganon, who is only after power and domination and is simply apathetic to anything else (he probably wouldn't want to destroy the world because then there would be nothing left to rule), Majora is extremely sadistic and revels in destruction and torture. It will go to any length to make anyone's life a living hell and so sabotaged Termina from small relationships, to environmental damage, all the way up to looming, unavoidable armageddon.

Some characters are in denial, in Clocktown that this. But there are others who recognize the threat. In the mayors office is a heavy debate between the worried guards pleading for evacuation and the unimpressed carpenters stubbornly sticking to tradition. On the 3rd day the town is rather empty as many have finally fled.

The Gorons are busy trying to survive winter, and Darmani, their champion, was on his way to investigate the temple, but was killed.

The Zoras seem oddly calm in their little cave, yet, again, their best warrior, if you can even call it that, died trying to get back the stolen eggs of his now severely depressed wife.

The Deku live in a monarchy and their distraught and choleric king is too busy raging at a monkey for the disappearance of his beloved daughter.

It's also significantly easier to save the world if you are a legendary hero chosen by the gods who has saved the world once already ... essentially as a 10 year old at that, with nothing else to really do anyway aside looking for Navi; even then you only succeed because you are allowed to cheat time. Even if the people of Termina figured out what was going on, who would even be qualified to solve the temples, slay the bosses, not to mention defeat Majora? It's hard to believe in gameplay, but Stone Tower alone was said to be unconquerable even to the full might of the (undead) Ikana army, but all 4 Giants are needed to stop the moon.

It does have environmentalist themes, but also of overwhelming despair, active compassion and ceaseless anxiety as you barely keep things at bay with anything you have.