Well, let’s not let it die an ignominious early death, and keep it alive for as long as possible.
And as far as the point regarding Gringotts, it is not particularly shver. From here I drift into conjecture, but…
Enter, stranger, but take heed
Of what awaits the sin of greed
For those who take, but do not earn,
Must pay most dearly in their turn.
So if you seek beneath our floors
A treasure that was never yours,
Thief, you have been warned, beware
Of finding more than treasure there.
The motto of Gringotts tells us all we need to know about it’s ethos. It is, as far as we know, impenetrable to true thieves, those who act out of, and I quote, ‘greed’, and ‘those who take, but do not earn’, ‘a treasure that was never yours’.
And if Dumbledore taught us one thing, it is that magic is not black or white, but contains many shades of grey. When one comes up against magical protections, their daas is taken into account, this being the reason Harry could get the Philosopher’s Stone and Quirrell couldn’t. So if we can make the connection, we find that the protection Gringotts promises will guard the treasures the client earned, against those who do not deserve it and desire it out of greed. But the creed does seem to suggest that it would be easier for a selfless thief such as Harry, to take from the Malfoys’ vault that which itself was originally stolen. Essentially, that the magical protection does not apply to hagoinav min haganov.
At this point, you probably will taineh that the metzius was that the plan Harry devised worked, and why should that not be the case for your average thief. To this I will defend my earlier point by saying that what’s to say your average thief will find it as easy, and not encounter as yet unknown magical protections activated by evil intentions. And furthermore, Harry had incredible luck in succeeding, not to mention the help of a former employee, and 99.9% of thieves would probably have been foiled by the extensive protections.
And lastly, just to cover my back, maybe the involvement of the Death Eaters in Gringotts (remember, that’s why goblins such as Griphook left in the first place) led to issues with security at the bank. This could be due to: The Death Eaters messing around with the ancient protections, the best goblins such as Griphook leaving, those goblins sabotaging security before they left, and lack of motivation among the remaining goblins.