Using Tyranny of Majority principle, suppose a new link (may be randomly) is developed between two disconnected components with m & n (m>n) nodes. In Authorities and Hubs method, A & H will change completely due to this new link. This shows that A & H is not robust to small changes.
On the other hand, Markov chains always puts a weak link between all disconnected components, hence any such small change will not significantly effect the page rank.
-Rashmi Dubey
