Jose has fought twice per year, except for 2011, when he fought just once. Cruz was out for two and half years before being stripped of his title. That's a good example of holding up a division.Aldo missing 5 title fights is actually not a moot point. He's not dependable. As a champion that's the worse thing to be because it holds up a division.
Also, I doubt Conor has any leverage when it comes to demanding an interim title fight. This is about the UFC trying its best to recoup the millions they spent traveling the world promoting Mr. Undependable versus Conor and the only way to still keep Conor on the main stage and give the fight as much value and meaning as possible for fans is to make an interim title fight between him and the No. 1 contender, Mendes. From a business stand point, I don't blame them at all.
And reporters have been suggesting Conor was the one who demanded the fight be for an interim title. He was not obligated to take the Mendes fight on short notice, so he did have some leverage to negotiate.