Why are so many people so adamant that Ron Paul could win the Presidency?

Because he's a person who speaks to people. He fights both democrats and republicans if they're not loyal to the constitution and he makes a lot of sense. Dr.Paul speaks to a base that is often forgotten by the D.C establishment and those are the people that are adamant for him to become president. If any politician adheres to his principles(or at least theirs or have some) then getting that popularity should be a cake walk).