Many cheesecake recipes do not call for condensed milk, among them the Kraft Dairy house recipe and professional chef Tyler Florence's Ultimate Cheesecake recipe. These recipes use, respectively, sugar and eggs and sour cream and eggs in the mix, which condensed milk would occupy in certain other cheesecake recipes.
Tyler Florence's Ultimate Cheesecake is made with a cinnamon and graham cracker crust adhered with butter. The substance of the cheesecake itself is primarily softened cream cheese combined with eggs, sugar, vanilla, sour cream, lemon zest and blueberries. The full assembly takes its sweetness and flavor from sugar and vanilla and has no need for condensed milk.
The Kraft recipe uses cream cheese fortified and puffed by eggs and sugar. This simple concoction is deposited on top of a similar graham cracker crust which, like the Florence recipe, is cemented with melted butter. The contrast between the firm crust and the airy cheesecake makes for the dessert's signature profile.
In general, the more elaborate the cheesecake recipe the less likely it is to incorporate condensed milk. Letting cream cheese and other ingredients like eggs and sour cream compose the bulk of the cake gives it a rich and flavorful formulation that only improves as the cheesecake sets overnight.