I shop at Aldi every week. As I've mentioned in my article published on Fool... there have been queues outside it before 8:00am in the morning. The car park is practically always overfull to capacity all the time during the day. Aldi are expanding rapidly in opening new stores too.
I think there is only a certain level they will be able to obtain because some people just won't do the Aldi experience, and some people do have 'brand loyalty'. If there isn't an Aldi too close I can't see many people going out of their way to visit one. It's not exactly a 'fun shopping experience'. You can't get many brands in Aldi still, but slightly more than before. But it just goes to show the MAIN thing MOST people care about is price!
So Sainsbury's should shift focus away from more 'green' or 'charity' approaches to just cutting prices- which they have been doing to an extent.