This is exactly how innovation is supposed to work - if a rival company (or a new entry to the market) comes up with a better solution then you have to innovate to survive. It's exactly why competition is important. It forces companies to improve what they offer. If they can do it in clever ways that don't cost much, that's even better. The business wins and the customer gets a better experience.
If Amazon has shocked the supermarket industry in to action then that's awesome.