Why did Carl Albert not become the President?

Carl Albert, who served as the Speaker of the U.S. House of Representatives from 1971 to 1977, did not become President largely because he was never in line for the presidency. He was a key political figure during the Johnson and Nixon administrations but was not selected as a vice-presidential candidate nor did he run for the presidency himself. Additionally, following Richard Nixon's resignation in 1974, Gerald Ford, who was the Vice President at the time, ascended to the presidency, further limiting Albert's opportunity for the role.