I mean, as smaller objects become more valuable, it becomes harder to find a place safe enough to hold them. And banks don't make money off safe deposit boxes - they're loss leaders to get banking customers.

However, the number of places where you can more securely store small objects with excellent and armed security exploded in recent years. They are currently used to host servers and other internet facing computers. I'm sure they'll store a similar rack-mounted box containing your will if you offer to pay them.