Dave,
That seems to be the first time you've suggested putting something in place of 'the crown' in this matter. But replace it with 'the state'? Would governments of all colours have the same 'veneration' for our history? Would some governments see the finding of a massive treasure as a way to help their funds, rather than paying the finders?

Until a good alternative is suggested, and thought through, the current system works. Hence the prosecutions.