Complex sentence: In more formal speech, the pronoun "one" serves this function; but as a pronoun (notably "not" when it signifies the number 1), it is felt to be somewhat awkward, and is infrequently used outside the most formal styles.
Split into simpler sentences: In more formal speech, the pronoun "one" serves this function. While "on" remains at home in formal French, "one" as an English pronoun remains somewhat awkward, and is infrequently used outside the most formal styles.