Its impossible to tell, but the sense of passage of time must have been dramatically different in earlier periods of human development.
Persistent rituals passed on from elders to youngsters, oral transmission of huge poems and other such "low tech" information tools must have given some structure to what otherwise might have felt as an eternal reboot.
I read somewhere (don't recall exactly where) that your sense of the passage of time is directly related to how much things change because that impacts how many memories you form. Essentially, when every day is the same, not many new memories are created, so you don't notice time passing (New Years was just a few weeks ago, how can it be July already!), but when things are constantly changing, time passes much more slowly. When you're a child and non-stop learning and exploring, 3 months seems like an eternity.
I wonder if technology development has a similar effect. When the world essentially remains unchanged for your entire life, things must seem much faster with days blending together.
Having been to jail, here's what they say, "the days pass like years, and the years pass like days." Which is a hugely accurate interpretation of what happens. Nothing happens all day, and every day is the same, so the days drag on in the most mind-numbingly tedious fashion. But then you wake up and you notice six months have passed without you being able to name a single thing that happened.
Herzog talks about this a bit in his cave-painting movie[0]. It's fascinating to think that for thousands of years, our ancestors lived without any significant change to their world. I like to imagine that they were pretty happy with that (subject to the normal animal stresses of survival) -- but as you say, it's impossible to tell.
The persistency that you're describing is key. I'd like to think that previous generations were far more content with time and what is associated with it. The mundane of the day-by-day, aging, death, etc.
Persistent rituals passed on from elders to youngsters, oral transmission of huge poems and other such "low tech" information tools must have given some structure to what otherwise might have felt as an eternal reboot.