Jewellery insurance - how much is enough?

Call me Jack.

Here's something else which annoys me, those companies insuring "old for new" (check your policy wording).  Surely if you get a piece of jewellery appriased at, say, £5000 by a reputable and qualified NAG jewellery valuation expert, then if you lose your insured jewellery you should be offered your replacement at exactly £5000 if it can be replaced? (to my mind that means by finding another piece by the same jeweller to that value or having the piece remade by a jeweller of your choice; the insurance company paying exactly £5000 to that jeweller and you providing more funds if necessary).  

Lets say you can't replace this piece like for like as another does not exist. Then surely you're entitled to receive £5000 in cash if you decide that is what you want.  Perhaps you don't want to replace that piece of jewellery because it has sentimental value which can't be replaced, or that it was an antique piece, an heirloom, which you want to replace with something else.  The point is you paid the premiums for £5000, surely you should get £5000?  Am I being thick here?

Here's someone who subscribes to the insurer's way of thinking - click here to see it - Is he actually saying what I think he is? The high street jeweller is really selling you an item for £5000 when its actually only worth £1750 the next day as that is what the insurer will give you in cash if you don't accept their preferred jewelers vouchers? Oh, and that's OK cos the whole reduction idea is built into the premium? I think if its really like this guy says, which it appears to be, then what's the point of an insurance valuation or the insurance? Its clearly all a con! Somebody do let me know because I'm losing the will the live here!