Re: I hate to say it but....
"There is absolutely nothing in luxury products that guarantees better quality or durability"
Price is one part of the context surrounding the "implied terms" of quality in the UK's Sale of Goods Act (SOGA). A £600 washing machine would usually be expected to last longer than a £150 one, unless the more expensive one was for a specific low volume use (e.g. in a caravan) and the buyer had used it as if it was for normal volumes. But a premium product like a Louis Vuitton bag is not always more expensive because a "reasonable person" has a higher expectation of durability. One might possibly have a case with such an item if it were badly made, however (as 'freedom from minor defects' and 'appearance and finish' are also possible implied terms).
The whole SOGA is based, very reasonably, on what a reasonable person would expect. It is quite possible a judgment would take into account that a reasonable person knows that a Mac will be more expensive than a similar specification PC and that the premium implies qualities other than increased durability (compared to the PC) --- but it is also quite possible that a judgment would say that an expensive computer should last longer in normal use. If it turns out you've been maxing it out 24/7 the judgment may be different again.