Content Expert Saxophones
Until teachers actively encourage (e.g.) C trumpets or C clarinets it won't happen -
I am a teacher, and since my young students generally start saxophone because they are in school, I would never encourage them to do anything other than start on Eb or Bb horns, since C-pitched saxophones are not welcome in school bands.
With regards to my adult students, again, if they have plans to join community bands, which is in reality where most adult students will end up playing, if they play in a band at all, I would have to steer them towards an Eb or Bb instrument, because in those bands too, C-pitched saxophones are generally not welcomed.
Many adults do not plan, or cannot afford, to purchase more than 1 saxophone. So buying a C pitched horn to start, would not be something I would feel comfortable doing. I would be severely limiting my students' ability to play with others.
Now having said that, if one of those adult students said to me they wanted to learn sax in order to play with their church's worship band, that would be a different story. In that case, a C-pitched sax would be a natural option for them.
BTW, yes, I have some C-pitched horns. I have a mint-condition (I'm only the 2nd owner) straight neck Conn (love it), and a Martin Handcraft which needs a rebuild & is currently totally unplayable. (It is acting as "wall art" at moment.) I must admit, the Conn soprano Pete linked to that Junk Dude currently has for $1300 is very pretty and tempting, but the fact is, I don't use my Bb sops enough, or my C melody at all (never have), so I can't justify the expense for yet another horn that will sit around, and not earn its keep. (I already figure I'll have to gig with my bass until I'm 70 to justify it. ;-) )