In a sense, as you more or less point out later in the article, everything does occur 'at once' in that all experience is NOW.

And, to experience anything is to experience a changing something. Our senses 'detect' change. Photons interacting in eyes, pressure variations in ear, chemical reactions on tongue. Even thoughts. Neurons firing, things changing in our brain.

But that continual change is at odds with our 'experience' of ourselves as an unchanging 'me.' I believe it is in that dissonance, between 'me' everlasting and world ever-changing that gives rise to our experience of time.

Thanks for the read! Worthy and thought provoking.