Málokdo, málokdy, and mnohdy

Czech málokdo (few people, hardly anyone) and málokdy (rarely, seldom) are composed of the indefinite pronoun/adjective/quantifier málo (little, few) and the interrogative pronouns kdo (who) and kdy (when). There is also the form mnohdy (frequently, often, oftentimes, many times), ultimately also from mnoho plus kdy, instead of the full form mnohokdy. There was an assimilation as the h in mnoho, followed by the g sound in kdy (kdy sounds like gdy), both guttural. The funny thing, though, is that there exists no mnohokdo or mnohdo, with the expected meaning of many people.