"It may be as simple as seeking a personal challenge. The sons have effectively been given everything they've got. Building something from (near) scratch as their father did with Westfield might be a source of personal legitimacy for them."
@Reaper11
In pursuit of ..."personal legitimacy"?
You are joking, right?
Steven and Peter Lowy are not some 25-year old punks, fresh out of uni and living in dad's shadow.
They have served as senior executives both outside, and within, the Westfield Group for decades in fields such as investment banking, operational management, marketing, commercial management and strategic management, including the past 5 or 6 years as co-CEO's of Westfield Group.
Steven is 55-years old and Peter is almost 60.
They are highly credentialised in their own rights - more so than probably 85% or 90% of directors of publicly-listed companies in Australia - and I'm sure they have absolutely zero need to prove anything to anybody, including themselves.