I didn't want to imply that you can just go off on a shopping spree and spend a few 1000s euros on clothes. But if your bag is delayed, and there are essential items in there which you absolutely need right away, you need to buy something fairly expensive, and can proof that you have to, I can't see that a court will reject your claim. I can be mistaken, but I thought the EU regulations had an upper limit for this (something like 4000 SDRs?).

As well I'd like to expect that your luggage has to same probability of arriving at your destination whether you travel on a cheap or expensive ticket...

I personally would never need to spend a large amount of money as I would never take anything that expensive (and needed immediately) in hold luggage.