Paywalled but some background for readers outside Australia:

The supermarket duopoly Coles/Woolworths have had a pricing war by selling substandard 'milk' at a loss to encourage customers through their stores. The result has been many farmers and smaller dairies struggling financially, e.g the Murray Goulburn cooperative forced to sell its operations to Canadian Saputo recently. FWIW, I normally buy Jonesy's and the local deli has recently started selling St David's - processed in suburban Melbourne.

A2 is thus one smaller brand seeking market differentiation through improved product - it all tastes just like milk to me but I then don't have the protein intolerance.