"Contesting a Will" is not new
Another high profile Estate and another claim on it by family of the deceased.
The idea of a relative being able to "contest a will" may seem like a relatively new development in the law, but its actually been the case in NSW since 1916 (Testator Family Maintenance and Guardianship of Infants Act), and the concept itself can be traced right back to the Roman Empire, where courts could set wills that unjustly failed to provide for close relatives.
In the UK the concept of "testamentary freedom" (being able to do whatever you wanted in your will without challenge) was king between 1540 and 1938, but in the colonies like NSW, and starting in NZ, the idea of varying or set aside a will because it did not provide for close relatives had gained traction since the late 1800s.
This was because of, at least in part, the Womens Rights Movement, which saw testamentary freedom as an issue because it often left widows disinherited and in need of protection.