Unless you leave an endowment for the perpetual care of your keys, it is likely they will be put in storage or sold as surplus inventory. The proceeds from the sale of our keys may go for buying paper towels. This is hardly a glamorous thought, but not far from reality. Museums, public and private come and go. Their backers and leadership changes.
Small museums come and go.
They are usually the passion of one person. When that person has a shift in life's priorities, the museum and the contents are gone. If we feel compelled to leave something to a museum, then we should leave them a few items such that the museum can assemble a small telegraph office or depot. This is only a small piece of most collections. If the pieces are relegated to storage or become surplus, not a whole lot of harm is done.