I think there is a market for it, but a large number of consumers feel "held hostage" by technology. They're just being told that they can't have this feature anymore, and then all the major companies remove it simultaneously (via the standard mechanism of copying Apple, of course).
Even if you wanted to "vote with your wallet", you couldn't.
There are no more phones being sold at reasonable sizes (besides the iPhone SE, which will probably go away soon).
None of the current big-name flagships (this S9 potentially being the exception) have headphone jacks.
If my current phone (an SE) breaks I'm not sure I'll buy another smartphone.
