The predecessor to this drink was called the John Collins and used genever liquor. When Old Tom gin gained popularity in the mid to late 1800’s they changed the name to Tom Collins and used Old Tom gin instead. Old Tom gin stopped being produced in the 1930’s.
Unlike the John Collins which can be either genever or London dry gin, the Tom Collins only uses Old Tom gin. That meant that from 1930 to 2007 there was no way to order a Tom Collins as Old Tom gin wasn’t produced between those years.