What is the reason someone from senate of house positions could not be president?

The framers' failure to provide a method for filling a vice-presidential vacancy continued to plague the nation. In 1792 Congress made a first stab at addressing the problem by adopting the Presidential Succession Act, providing that, if a presidentshould die when there was no vice president, the Senate president pro tempore and the Speaker of the House of Representatives, in that order, would succeed to the office. In 1886, responding to a concern that few presidents pro tempore had executive branch experience, Congress altered the line of succession to substitute for the congressional officials cabinet officers in order of rank, starting with the secretary of state. In 1947, after the vice presidency had been vacant for most of a presidential term, Congress again changed the line of succession. Concerned that cabinet officers had not been elected, it named the House Speaker as the first official to succeed if a president died during a vacancy in the vice presidency, followed by the president pro tempore.