Why still manual lenses?

I can think of at least 4 possible reasons why companies like Samyang and Voigtlander have produced manual focus m43 mount lenses:

• they would have to pay substantial fees to Panasonic and Olympus for being granted full access to the m43 lens protocols that determine things like autofocus and correct aperture control for exposure.
• for video shooting manual lenses are often preferable.
• some photographers, particularly those of us who are a little older, quite like to experiment with manual exposures when time is not of the essence.
• they are cheaper to produce, so can be an entry to the m43 market (and for other mirrorless systems) without having to compete with Panasonic and Olympus from day one.

You can probably think of other reasons as well.