In the German market, ALDI/LIDL/REWE currently have a healthy oligopoly. Why destroy end user prices and your own margins by automating?
Amazon is not directly attacking their store-focused model because for the billions needed in investment to reach the automation needed for main-stream adaption, they can get way higher margins in other categories (e.g. non-food).
IMHO the perfect supermarket of the future is not food delivery, but a drive-in/pick-up model where you can go 24/7 and where your order is packed 100% by robots. Until we reach this point in terms of technology, the traditional supermarkets will not change due to the above-mentioned oligopoly.