It's probably a hill that gets muddy. Everyone walks in the same spot because they've been flattened out like stairs and you slip less. It does happen naturally over time and many feet.

Totally fair question. It definitely happened naturally is the TL;DR. Edit: pic below from Google maps.

There's a section of tarmac not in the picture where I took it and a path leading to the right at the top just below the bushes. Those steps happen near the corner of the tarmac. Myself and my kids have used them countless times and always followed the steps.

The alternative route is off about 50 metres to the left and a slow incline followed by a much longer walk.

The incline you're looking at is steep enough that any kind of foothold is going to be taken by the next person... And so it happened. :)

I've had this one in my camera roll since forever and it came up in a memory. There's been a fair bit of building work done there recently which I vaguely think may have damaged or possibly destroyed the steps but I'll check.

I'd bet money it's on Google maps but I don't really want to dox myself.