The popularity of Shiva has something to do with the destructive aspect of change. And this is one of the most obvious.  Noticing change is a profound state. It is another similarity of death. It is experienced as the passing of things into the past.  This is time itself

There also is Brahma.  This is the becoming, the creative.  This is the aspect that is the future.

The other aspect of God is the preserver, Vishnu.  Vishnu is what keeps Brahma from becoming Shiva.

It makes sense to me that in Western terminology, Brahma=Father, Vishnu=Son, and Shiva=Holly Ghost.

This is at least at first pass.  Of course it isn’t practiced at all the same way.

Nevertheless, if one focuses one’s attention on the passing of time, one becomes in harmony with Shiva and that’s why the mantra is so universal.