In today’s world there are not that many functions where the Royals wear tiaras or crowns, even jewelry. IMO I think the current Royals just don’t see the need to buy more pieces when they don’t wear what they have. It is a shame though that some history is leaving the family.
Then there would be remarks from the public why are they Royals spending all this money on jewelry, even if is a heirloom, when they don’t wear what they own. The Monday can be used better else where. The money could be private or public money, but the public will not care they just see the money spent in better ways, the just buying it to sit in a drawer.
A no win situation for many