Because most of the cattle areas of the country have had such brutle hot summers with extreme droughts, beef prices have practically doubled in the past few years. What probably happened is that when it came time to renew their "angus" beef contracts, the price was too high and the item is likely already priced out of their target demographic. The ray of hope that they're offering is probably them trying to find a new supplier or an attempt to beat down their supplier by pulling capacity in another product.
If Australia hasn't had the same problems, it would reason that you'd still see it there.
No clue about the chicken selects....that's probably motivated by logistics, fryer room, and lack of demand maybe?