Yes, societies with luxury brands and other unnecessary benefits can be sustainable. This is because the presence of such items reflects that society's willingness to let individuals make choices about how they allocate their personal resources. A more homogenized society, which would limit the number of "plush" amenities, would be repressing the individual's will to power, which would ultimately lead to that society's demise.
The present state of society is not sustainable, but that doesn't mean that we can't find a way to be sustainable. One of the main reasons that our current situation is not sustainable is that the way we fuel our lifestyle and activities are fossil fuels, which are very finite and will eventually run out. But we are already looking towards new ways to power our lives which can provide more energy with less downsides if they are developed properly. These will become more and more realistic as time goes on. Scientists are even gaining ground in areas like fusion power, which is a cheap way of creating almost endless energy. So there is no reason that we should have to sacrifice luxury items in order to become sustainable.
I think it is good for a society to have high end brands, because it gives a lot of people a goal to work towards, and something to have a goal to aim towards. It does not hurt anything to have a high end product in the market where you live.
Any consumer society such as one that allows for luxury car brands can never attain sustainability. The creation of luxury cars requires the use of finite resources, which eventually run out, which is not sustainable. The notion of luxury car branding would not even exist in a society that was actually concerned with sustainability because they are example of excessive waste and not necessary to the maintenance of life.
I personally think that society has attain sustainability if it allows itself to have luxury brands such as cars because some people think that having name brand is always the case to every success and that is not the case. I personally think that society has attain sustainability because all money is not meant to always being spent.