Why does English have 'interception'/'intercept' instead of 'interception'/'interceive'?
Because some English speakers who felt the need to use the Latin word interceptus in English, did so, creating intercept (Interception came later in a similar manner).
Conceive, deceive, and perceive have similar Latin origins in their -ipere/-eptus (depending on conjugation) endings, but came into English from Old French at an earlier stage, and after they had already been altered to fit Old French.