The power of brands in consumer culture has been much criticized, for encouraging needless consumption and masking the environmental and social costs of production. But luxury branded goods surely have some redeeming qualities when compared to the own-brand or white-label products which can be bought cheaply in a supermarket.
They tend to last longer.
In the case of items like watches and electronics and cars, the higher price of prestigious brands is usually dictated by costs such as craftsmanship, design and marketing – in other words, job creation in fields with low direct impact on the environment.
With food and clothing, it could be argued that a well-known brand creates a link between the consumer and the producer, thereby exposing the producer to consumer boycott in the case of environmental or social abuses.
So which is more sustainable? Buy cheap clothes or electronics but in greater quantity? Or support the design and marketing budgets of multinational corporations?
Update: This recent opinion article suggests that luxury clothing is indeed more sustainable than cheap clothing, by definition. The author's main argument is that high-value production means less consumption and less wastage:
If you buy more expensive clothing, it doesn’t guarantee that your clothes will be exceptionally well-made, or that workers haven’t been exploited in their making. [...] And even expensive clothes are responsible for polluting the environment when the textiles they’re made from are dyed, and when they’re eventually discarded and left to sit in a landfill. But it may reduce the likelihood of worker exploitation. And if nothing else, spending more should mean buying—and wasting—less.
To clarify, the premise of this question has been amended to assume equal expenditure. At issue is whether or not luxury goods are more sustainable – dollar for dollar – than budget items, taking into account the impacts at each stage of the production chain.