This article suggests that the democratisation of luxury brand goods diminishes its rarity eroding the very quality that falls under the definition of luxury. If you look at Apple as a case example - their devices are expensive and widely accepted as the highest quality for their respective field which points towards them being luxury items. However, they are hugely widespread with an Apple product, on average, in almost every household in western civilisation. On that basis I think the iPhone falls foul of being considered a genuine luxury product when compared against, for example, a Vertu mobile phone.
Despite economic difficulties the number of ultra-high net worth individuals continues to grow. This doesn't speak volumes for financial equality but it does show an increasing demand for luxury goods and services.