AFAIK Sony sell a lot of cameras to the general public but maybe Fuji sell more to people who frequent photography forums. The A6xxx series in particular is AFAIK (again) a massive seller but there's next to no chat about it on these forums. I think forums give a skewed view if you're using them to gauge what's selling best.
I am sure you are right about sales . Sony have done far better from marketing to the general public, especially to those familiar with their electronic goods and other household products. Which is probably why Sony is less concerned about maintaining a continuity of products that appeal more to serious"Photographers".
Sony most definitely are serious serial innovators. but have a tendency towards a butterfly brain approach to their products that has never appealed to me. Probably because they do not design cameras that suit the more traditional approach to photography, or that have particularly logical layouts of controls, handling or menu systems.
Fuji on the other hand are firmly grounded in Photography. they understand how photographers work and think.
Continuity is a serious part of their planning. In as much that their firmware approach seems to be open ended, so that features can be added or amended at a later stage to existing hardware. Rather than only introduced on new models.
When Fuji do introduce new models they ensure that the wishes and needs of real photographers are solicited, and are far less likely to simply add innovations as sales gimmicks. or to raise "numbers" like pixels or ISO to outdo those of their competitors. The primary aim of their developments always leads to better tool for the job in hand,
The Fuji X series of cameras is neither aimed at, nor has made great inroads into the consumer market place. In fact, that is a market that they appear to have almost totally deserted.
Their sole digital camera in that field now is the S9800 bridge camera,. supported by their Instax range of fun instant print cameras.
If anything the recent introduction GFX 50s and the concentration on X cameras, indicates that that Fuji are moving, with considerable investment and planning, to an almost exclusively professional and advanced amateur photographer market place.
This is a concentration that no other leading camera maker has attempted in the digital era.