The inequality doesn't seem related to inheritance, but to entropic decay in records-keeping. Just as selling stolen goods creates transitive liability back to the original thief, so too would inheriting stolen goods (with both cases obviously requiring sufficient evidence). And existing liabilities must be covered before any inheritance transfer—inheritance or otherwise—can justly proceed. However, the passage of time naturally serves to introduce uncertainty and disperse both obligations and claims, eventually making any attempt at recovery first cost-prohibitive, and eventually impossible.
For example, imagine an easily-identified heirloom that is always explicitly willed to the eldest child—it may be easy to find a rightful owner today, even if it was lost in the 1600s. Contrast that with a similar heirloom that is not so meticulously tracked, the mention of which was eventually dropped from a descendant's will in the 1860s. Now contrast that with a claim of restitution over a failed business venture between people that died before 1900 without resolving things, and never explicitly mentioned the affair except perhaps in stories to their grandchildren.
In principle, obligations exist in all three cases (up to the limit of net inheritance). In practice, only one might be worth pursuing—making the others irrelevant except for academic discussions like this.