I've never heard "I'm just here for the paycheck."

Maybe it's because of the cliché we've learned to avoid saying it.

But I have observed an intensive defense of the right to remain the same.

Yes, your paycheck is generally associated with the here and now, what has already been done. 

However, the here and now is changing.  Maybe not suddenly, but gradually. 

Even though the weeks feel similar your customer is changing.  Subtle changes that feel like no change at all.  Like yesterday was the same as today.  Except it isn't.