Well, there is a profit opportunity for the well capitalized and motivated: a mukluk that you can purchase on line or at CANEX or your friendly kit/surplus shop.
Much like Danners, SWAT's or NEO's, real kit a solider can actually use without being hurt/broken by using it, or left in the rather embarrassing position (like I have been repeatedly over the years) of waddling about in the field after the sole came off the issue boot...
AS for the liners, I suspect that there are modern materials out there which can either wick away the moisture (think of Underarmour cothing), or is made out of material that simply won't get moldy (something like fabrics made from basalt. ROXULTM is an example of that sort of material used as insulation; it is also sound retarding and fireproof in that format, and not all that expensive either.
This company makes a basalt fabric, for anyone wanting to do the research.