As the main cook and grocery buyer in our household, I am not surprised by the current years differences between our two big supermarkets.
I am lucky to have one of each in my local shopping center, so can and do shop at either. In general Coles have been doing a much better job of late in my view. Better bakery and meat options. Better weekly deals. Few more staff on the registers. And in turn Coles seems busier most times I visit.
Not investing in either and most likely things swing back the other way at some point in the future again. But as always, in retail, it's a detail business and all the little things matter.