That's how I took it watching the opening sequence, but I'm down with a cyclical universe as well.

its not a mystical sign, its a series of cuts to indicate the passage of time. It is to show that they walked for a long time.

I've been working on a theory that they're different instances - different universes - within the greater multiverse.

We, all of us, do the same thing, on the same day, over and over and over and over and over.

The magic of the Traveler is that all of the experiences, knowledge, and power are summed into one essence, somehow.

We, the Guardians, it's champions, are rising from the ashes in an instant. Or, over the span of a few days.

The tower doesn't really change. I kill Sepiks Prime, and again, and again. Sometimes I die, sometimes I don't. Sometimes I am with the group that destroys Aetheon, and sometimes not. Sometimes Aetheon lives.

Those astronauts are all waking towards the Traveler in the same event, just different universes. The Stranger talks to scarab sometimes, and sometimes she talks to yakaman.

Or, if not different universes, then different simulations, like the Vex grimoire cards.