First of all, they are in a museum that's only free to visit of you live near that museum. They are already stolen. For the rest of the world that actually owns them, they already metaphorically have 'some rich asshole who got them and put them on their yacht never to be seen again'.

For many of the countries that own them, there will be thousands of inhabitants that may never be able to afford to travel to the UK to view them. It's unlikely that the British museum will ever tour with them, as once they arrive in almost any country, they will likely stake a claim to have their property back.