During the era of the typewriter there were a few kinds of basic designs. The (afaik) most well known is the type bar design, where each key is connected to an individual type bar that hits the paper when the key is pressed, each type bar carries the uppercase and lowercase shapes of a single letter. The other variant is the type wheel or type ball design (or generically the single type element design), where a single ball or wheel shaped element contains all the letters. The mechanism rotates and/or tilts the wheel/ball before it strikes the paper so that the right letter is imprinted.
Type wheel/balls have some advantages over type bars: They cannot get stuck, and the entire wheel/ball can be replaced to change the font. The Blickensderfer, one of the early wheel operated typewriters, is often described as being much simpler than other contemporary (often type bar operated) machines, containing only a quarter of the moving parts of other contemporary typtewriters, so the type wheel mechanism appears to not necessarily be more complex than type bars.
During the last decades of the typewriter era, the electric type ball operated Selectric machines where very popular as higher end typewriters, but I have the impression that type bars were more common in manually operated lower end machines.
There seem to be clear technical advantages for type wheel/ball designs. Why were type bars so popular for manual typewriters?
(This question makes a few assumptions, which may be wrong. Please tell me if that is the case.)
edit: Clarified the question that it is about manual typewriters, add pictures