His path to the presidency never went through the ticket, he replaced Agnew after the ‘72 election, then got “promoted” 18 months later. By the time he was on the “ticket” in any way it was as incumbent.
What you offered up is in no way comparable to this:
Since 1900 Britain has had 22 different Prime Ministers. Our list below shows that in that period there have been 14 occasions on which 13 different Prime Ministers have come to power other than through a general election.
| Year | Prime Minister | Party |
| 2007 | Gordon Brown | Labour |
| 1990 | John Major | Conservative |
| 1976 | James Callaghan | Labour |
| 1963 | Sir Alec Douglas-Home | Conservative |
| 1957 | Harold Macmillan | Conservative |
| 1955 | Sir Anthony Eden | Conservative |
| 1940 | Winston Churchill | Conservative |
| 1937 | Neville Chamberlain | Conservative |
| 1935 | Stanley Baldwin | Conservative |
| 1923 | Stanley Baldwin | Conservative |
| 1916 | David Lloyd George | Liberal |
| 1908 | Herbert H. Asquith | Liberal |
| 1905 | Henry Campbell-Bannerman | Liberal |
| 1902 | Arthur Balfour | Conservative |
You can add Theresa May.