It's expressed in our language, our systems, our culture, our religion (Christianity is a religion based in a straight-line concept of time)
But what aobut those people in ancient Sumeria or Old dynasty egypt or the Harappan civilization. 2000 years with things changing so slowly as to be non-visible. This was also somewhat true in the Middle Ages, but still there would be some difference between your grandfathers time and yours in the case of kings and wars
These people would have had a completedly different mindset
So true, and yet, we're just one apocalyptic event from radically changing our world to something few can imagine.
A couple hundred years from something like that and mankind could be working our way back to something resembling the Harappans.
There's an interesting video game series, "Fallout" which explores a type of post-apocalyptic world.
Wonder how the Hindus came up with their time scale? They came up with measurements of time in nano seconds to a scale of 1.76 million years. They too were living in a world that was constant in a linear sort of way. Though the Hindus saw it as cyclical, and vast.