And the people who have a strong drive for the accumulation of capital/assets build armies and those armies shake down subsistence-living people for food and supplies in order to sustain themselves and suddenly you've got taxes again
Yes, thankfully modern liberal(ish) democracy(sort of) and the rule of law allowed us to exit this circle (well.. at least brought us much closer to that point than we ever were).
I believe that the claim is this: In the long scope of history, being able to accumulate money without having to be strong enough to defend it is really rare.
Depends on how you define saving. Hoarding perishable goods is of course a pretty natural behaviour but that only scales so much. Investment (i.e. owning more land or other productive assets than you can utilize directly yourself) seems pretty as opposed to communal ownership seems pretty "unnatural".
Not that I'm somehow implying that "natural" (whatever that really means, since using violence and coercion certainly seems like natural human behaviour) is somehow always superior to the opposite.
Being able to accumulate capital, at least without having to resort to extreme violence is also about as "unnatural" as it gets..
No taxes = No government = No excess (above subsistence level) accumulation of assets