People who do not like the ‘idea’ of a large corporation will always have smaller, more expensive ’boutique’ firms to shop at. What I found interesting when I was working at the Warehouse as a student was how many anti-capitalism types would come in and buy products there. Obviously the cost savings were sufficient for them to forget about their ‘morals’.

Now there are other social costs, as mentioned in http://tvhe.wordpress.com/2007/11/20/corporations-and-welfare/

Whether we want these more inefficient firms to be shut down as a result of our consumption decisions is a value judgment. If government cares about small and relatively inefficient local businesses more than the consumers of that product, then they should stop such mergers.

Now in your question you say ‘beyond our individual sight’ I can take that to mean two things:

1) The way the products are put together, so there is some health risk, etc
2) Predatory pricing

In the first case we always hear about bad multi-nationals with bad products, as local retailers are stuck in the society and are more responsible about the quality of their products. However, this will be incorporated in the price we as consumers pay, we know that there is some risk. Also, local retailers often sell a load of crap for higher prices, I know that was the case in Otorohanaga.

Predatory pricing requires barriers to entry and the level of effective competition. Barriers to entry may seem large in the super/mega-market industry, however this industry many different product types. At the product level competition can be fierce with effective competition from all over the show (butcheries, dairies, smaller retailers, etc). Entry into many of these smaller industries is not so difficult, and so the only constraining factor comes from cost (firm and transaction) advantages for the incumbent superstore (economies of scope and scale).

However, many of these cost advantages are disappearing with the appearance of internet shopping. Also as NZ is small, it is always possible for large foreign firms to enter the market if there are supernormal profits hanging around. As a result, predatory pricing does not seem to be a risk.